ABSTRACT
This case report describes a variation of the flexor digitorum brevis (FDB) with a separated muscle belly and tendon at the fifth toe. The narrow tendon and muscle belly for the fifth toe arose from the intermuscular septum between the FDB and abductor digiti minimi adjacent to the arising fibers of the FDB, separating from its other fibers. The tendon and muscle belly for the fifth toe became wider at the base of the metatarsal bones and narrower as it coursed toward the toes in a fusiform shape. The tendon and muscle belly for the fifth toe became thin at the midfoot and coursed just beneath the flexor digitorum longus tendon and entered the digital tendinous sheath. FDB variations including that described herein should be considered when performing various surgical procedures and evaluating the biomechanics of the foot.
ABSTRACT
The vasculature of the pituitary gland is discussed briefly and the details of an anatomical discovery of the vessels supplying the pituitary gland provided. Twenty latex injected cadaveric heads were dissected. Any vessels that were found to penetrate the sella turcica and travel to the pituitary gland were documented and measured. Additionally, 25 adult skulls were evaluated for the presence, size, and sites of bony foramina in the floor of sella turcica. Trans-sellar vessels were identified in 65% of specimens. There was a mean of 1.5 vessels per specimen consisting usually of a mixture of veins and arteries. The mean diameter of these vessels was 0.3 mm and the mean length from the sella turcica to the pituitary gland was 2.3 mm. These vessels were concentrated in the most concave part of the sella turcica. In bony specimens, the mean number of transsellar foramina was four. The diameter of these foramina ranged from 0.3 to 0.6 mm in size. The trans-sellar foramina were concentrated near the center part of the sella turcica and had no regular pattern. The pituitary gland receives at least some blood supply and drainage via vessels traveling along the septum of the sphenoidal sinuses and through the sella turcica.Knowledge of such vessels might lead to a better understanding of the vascular supply and drainage of the pituitary gland and would be useful during skull base approaches such as trans-nasal approaches to the pituitary gland.
ABSTRACT
The present case report describes an unusual variant of a missing medial tarsal artery (MTA) being replaced by the anterior medial malleolar artery (AMMA). The dorsalis pedis artery (DPA) did not give off any branches to the medial foot. The DPA coursed downward in the foot along with the superficial fibular nerve on the foot dorsum at the lateral side of the first metatarsal bone before entering the sole. In the medial malleolus, the AMMA arose from the anterior tibial artery and then ramified several branches, one of which descended to the medial talus. Thus, the possibility of a missing MTA being replaced by the AMMA should be considered by surgeons and radiologists when various surgeries are performed in the medial tarsal area.
ABSTRACT
The orbicularis oculi (OOc) is a sphincteric muscle of the eyelids, whereas contraction of the orbicularis oris (OOr), another sphincteric muscle, causes narrowing of the lips. Facial muscle fibers normally blend with adjacent muscles. However, muscle fibers connecting the various facial muscles that have different actions and that are located at distant sites, such as the OOc and the OOr have been rarely reported. Herein, we report a rare case of connecting fibers between the inferior margin of the OOc and the OOr. These connecting fibers were blended with the OOr between the inserting fibers of the levator labii superioris and levator anguli oris. Contraction of such variant muscles might affect typical facial expressions.
ABSTRACT
SUMMARY: The aim of this study was to clarify the diverse spinal compositions of the branches of the lumbar plexus in terms of their prevalence rates and thicknesses. Thirty lumbar plexuses extracted from Korean adults were used in this study. The nerve fascicles were separated and traced with the aid of a surgical microscope. The thickness of each spinal nerve component was calculated based on the mean of the largest and smallest diameters using digital calipers under the surgical microscope. The most common patterns of the spinal composition of the branches of the lumbar plexus were as follows: The iliohypogastric nerve (IHN) and the ilioinguinal nerve (IIN) arose from the ventral ramus of the first lumbar nerve (L1), the genitofemoral nerve (GFN) arose from the anterior division of the ventral ramus of the second lumbar nerve (L2), and the lateral femoral cutaneous nerve (LFCN) arose from the posterior division of the ventral ramus of theL2, the femoral nerve (FN) arose from the posterior division of the ventral ramus of L2-the fourth lumbar nerve (L4), with the thickest spinal component derived from the third lumbar nerve (L3), and the obturator nerve (OBN) arose from the anterior division of the ventral ramus of L2-L4, with the thickest spinal component derived from L3. However, when L5 constituted the FN and OBN, the thickest spinal components of the FN and OBN was L4. This morphometric study has measured the thicknesses of diverse spinal components that constitute the branches of the lumbar plexus after separating the nerve fascicles. The thicknesses of the various spinal components of these branches can be compared in order to understand which make the main and minor contributions to the lower limb.
RESUMEN: El objetivo de este estudio fue evaluar las diversas composiciones espinales de los ramos del plexo lumbar en cuanto a sus tasas de prevalencia y grosor. Se utilizaron treinta plexos lumbares extraídos de individuos adultos coreanos. Se separaron y trazaron los fascículos nerviosos por medio de un microscopio quirúrgico. El grosor de cada componente del nervio espinal se calculó con base en la media de los diámetros mayor y menor utilizando calibradores digitales bajo el microscopio. Los patrones más comunes de la composición espinal de los ramos del plexo lumbar fueron los siguientes: el nervio iliohipogástrico (NIH) y el nervio ilioinguinal (NII) surgieron del ramo ventral del primer nervio lumbar (L1). El nervio genitofemoral (NGF) surgió de la división anterior del ramo ventral del segundo nervio lumbar (L2). El nervio cutáneo femoral lateral (NCFM) surgió de la división posterior del ramo ventral L2. El nervio femoral (NF) surgió de la división posterior del ramo ventral de L2. El cuarto nervio lumbar (L4), con el componente espinal más grueso derivado del tercer nervio lumbar (L3) y el nervio obturador (NOB) surgieron de la división anterior del ramo ventral de L2-L4, con el componente espinal más grueso derivado de L3. Sin embargo, cuando L5 constituía el NF y NOB, los componentes espinales más gruesos del NF y NOB eran de L4. Este estudio morfométrico analizó los espesores de diversos componentes espinales que constituyen las ramas del plexo lumbar después de separar los fascículos nerviosos. Es posible comparar los espesores de los diversos componentes espinales de estos ramos para comprender las contribuciones principales y menores al miembro inferior.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , Aged, 80 and over , Spinal Nerves/anatomy & histology , Lumbosacral Plexus/anatomy & histologyABSTRACT
Fibers of the facial muscles occasionally extend, cross the midline, and connect to surrounding structures on the contralateral side, perhaps enabling the mouth to make more delicate movements and generate more facial expressions. This case report describes a variant in which the extended fibers of the mentalis crossed the midline and indicates the relationship of these fibers to the surrounding structures. Some of the deepest fibers of the mentalis descended inferomedially and crossed transversely just below the chin prominence to attach to the periosteum of the mandible on the contralateral side. The variation presented in this study shed light on the interactions of the mentalis with the surrounding muscles.
ABSTRACT
The aim of the present study was to describe a variation of the anomalous nasi muscle in relation to the surrounding structures. The anomalous nasi muscle was found in the left face of a 40-year-old female during dissection. The anomalous nasi muscle lay on the lateral side of the nose, and it originated from the frontal process of the maxilla. The origin of the anomalous nasi muscle was located medial to the middle part of the levator labii superioris alaeque nasi muscle. It ascended superomedially to blend with the deep and lateral fibers of the superficial layer of the procerus below the level of the medial palpebral ligament. The length and width of the anomalous nasi muscle were 11.9 mm and 2.8 mm, respectively. This report demonstrated a variation of the anomalous nasi muscle, which will be helpful for understating the nasal movements and nasal wrinkles.
Subject(s)
Adult , Female , Humans , Ligaments , Maxilla , NoseABSTRACT
This report describes a variation of the tendinous slip of the flexor digitorum longus (FDL) for the great toe. In addition, compositions of the long flexor tendons for all five toes were examined. The tendons of the FDL in the foot were investigated in 66 specimens of embalmed Korean adult cadavers. The tendons of the flexor hallucis longus (FHL) and the FDL with the lumbrical muscles were cut at the calcaneus and the metatarsophalangeal joints and were removed en bloc specifically to observe the FDL and the FHL tendons of the great toe. The tendinous slip of the FDL for the great toe was found bilaterally in the foot of a 52-year-old male. Its prevalence was two of 66 specimens (3.0%). The tendinous slip of the FDL for the great toe passed forward the great toe, and it constituted the superficial portion of the long flexor tendon for the great toe. The tendon of the FHL passed forward to constitute the deep portion of the long flexor tendon for the great toe. Thus, both the tendinous slip of the FDL and the tendon of the FHL composed the long flexor tendon for the great toe. The tendinous slip of the FDL and the tendon of the FHL for the great toe were similar in thickness; thus, each tendinous slip of the FDL and the tendon of the FHL were approximately one-half of the long flexor tendon for the great toe in thickness. The present study demonstrated an anatomical variation of the interconnection between the FHL and the FDL tendons, which will be useful for various surgeries and biomechanical research.
Subject(s)
Adult , Humans , Male , Middle Aged , Anatomic Variation , Cadaver , Calcaneus , Foot , Metatarsophalangeal Joint , Muscles , Prevalence , Tendons , ToesABSTRACT
The aim of this study was to classify morphological patterns of the lumbrical muscles and their anatomical variations in the hands. The lumbricals in the hand were investigated in 70 specimens of 45 embalmed Korean adult cadavers. The shapes of the lumbrical muscles were observed in 70 specimens and the distances from the distal border of the flexor retinaculum to the origins of the lumbricals were measured using digital calipers in 52 specimens. The lumbrical muscles were classified into 3 types based on their shapes, and also into 10 types based on their insertion sites. The average distances from the distal border of the flexor retinaculum to the origins of the first, second, third, and fourth lumbricals were +1.8 mm, - 1.4 mm, +5.1 mm, and +11.2 mm, respectively. The results of this study could be useful information for better understanding the function of the lumbrical muscles and for various types of diagnoses and surgery involving the hands.
Subject(s)
Adult , Humans , Cadaver , Diagnosis , Hand , MusclesABSTRACT
This study aimed to determine the number of branches of the upper and lower subscapular nerves and to classify the spinal nerve compositions of each branch. Twenty sides of the brachial plexus extracted from Korean adult cadavers were used in this study. The upper subscapular nerve was composed of three branches in 16 sides (80.0%), composed of four branches in 4 sides (20.0%). The lower subscapular nerve arose from posterior cord with one branch, innervating the subscapularis and the teres major muscles. In case of the upper subscapular nerve, the first branch was comprised of C5 in 40.0%, C5 and C6 in 60.0%, the second branch was composed of C5 in 15.0%, C5 and C6 in 85.0%, the third branch was arisen from C5 and C6 in 75.0%, C6 in 25.0% and the forth branch appeared in four sided was derived from C6. The nerve branch innervating the subscapularis muscle was composed of C6 in 55.0%, C5 and C6 in 40.0%, C6 and C7 in 5.0%. The nerve branch innervating the teres major muscle was composed of C6 and C7 in 65.0%, C5, C6 and C7 in 25.0%, and C6 in 10.0%. The injury was often due to an accidental damage or lesion of the subscapular nerve, these anatomical results may be helpful to predict the involving area of the lesion.
Subject(s)
Adult , Humans , Brachial Plexus , Cadaver , Muscles , Spinal NervesABSTRACT
Situs inversus totalis is a very rare anatomical abnormality, which is characterized by dextrocardia and "mirror image" distribution of abdominal organs. Dextrocardia and situs inversus have important surgical implications due to altered anatomy. The aim of this study was to describe the anatomical structures of the situs inversus with dextrocardia in Korean. Presence of situs inversus with dextrocardia was confirmed in a 72-year-old female cadaver during dissection in a gross anatomy course. It was observed by focusing on the positions of the thoracoabdominal structures. In this cadaver, clearly inverted morpholoiges existed in the structures of the thoracoabdomen except the kidneys. The left-sided kidney was located at a slightly higher level than the right-sided kidney although the liver was located on the left side. We reported herein a case of dextrocardia and situs inversus with incomplete inversion, which will provide useful information for accurate diagnosis and relevant surgical procedures.
Subject(s)
Aged , Female , Humans , Cadaver , Dextrocardia , Diagnosis , Kidney , Liver , Situs InversusABSTRACT
Many anatomists and clinicians who investigate the peripheral nerve concern about the composition of the spinal roots of each terminal nerve of the brachial plexus. From this viewpoint, the spinal root composition of the ulnar nerve is still unclear. Several anatomy textbooks describe that the ulnar nerve is composed of the ventral rami of the C8, T1 and often C7. There is no literature regarding the frequency and contribution quantity of C7 to the ulnar nerve. The purpose of present study was to determine frequency and contribution quantity of the C7 to the ulnar nerve. Fifty cadavers of brachial plexus were obtained from cadavers of Korean adults. The brachial plexus containing the ulnar nerve were extracted from the axilla and the extracted samples were immersed in Guanidine-HCl (0.2 M) for 2 weeks to soften the connective tissue around the nerve bundles. C7 was contributed to the ulnar nerve in all sides (100%). The numbers of the myelinated axons of C7 participating to the ulnar nerve was 1,452+/-429 (mean+/-S.D.). Thus the C7 can be considered as always participating component of the ulnar nerve, not often participation, although numbers of the myelinated axons of C7 was lesser than those of the C8, but similar to those of the T1. The results of the study provide a reference for accurate diagnosis and treatment regarding ulnar nerve injury due to various accidents.
Subject(s)
Adult , Humans , Anatomists , Axilla , Axons , Brachial Plexus , Cadaver , Connective Tissue , Myelin Sheath , Peripheral Nerves , Spinal Nerve Roots , Ulnar NerveABSTRACT
Cerebrospinal fluid (CSF) plays an important role in providing brain tissue with a stable internal environment as well as in absorbing mechanical and thermal stresses. From its initial composition, derived from the amniotic fluid trapped by the closure of neuropores, CSF is modified by developing and differentiating ependymal cells lining the ventricular surface or forming the choroid plexus. Its osmolarity and ionic composition brings about a change through the action of many channels expressed on the ependymal cells. Some newly discovered transient receptor potential (TRP) channels are known to be expressed in the choroid plexus ependyma. To detect additional TRP channel expression, immunohistochemical screening was performed at the choroid plexus of 13-, 15-, 17-, and 19-day embryos, using antibodies against TRPV1, TRPV3, and TRPA1, and the expression was compared with those in the adult TRP channels. The level of TRP channel expression was higher in the choroid plexus which suggests more active functioning of TRP channels in the developing choroid plexus than the ventricular lining ependyma in the 15- and 17-day embryos. All the expression of TRP channels decreased at the 19th day of gestation. TRPA1 was expressed at a higher level than TRPV1 and TRPV3 in almost all stages in both the choroid plexus and ventricular lining epithelium. The highest level of TRPV1 and TRPV3 expression was observed in association with the glycogen deposits in the cytoplasm of the choroid plexus ependymal cells of the 15- and 17-day embryos.
Subject(s)
Adult , Animals , Female , Humans , Pregnancy , Rats , Amniotic Fluid , Antibodies , Brain , Choroid Plexus , Cytoplasm , Embryonic Development , Embryonic Structures , Ependyma , Epithelium , Glycogen , Mass Screening , Osmolar Concentration , Transient Receptor Potential ChannelsABSTRACT
This case report describes an unusual communicating branch from radial to ulnar nerves in the axilla region on the right side of the Korean cadaver of a 59-year-old male. The brachial plexus containing the communicating branch were extracted en bloc. The extracted specimens were immersed in Guanidine-HCl (0.2 M) for two weeks and then treated several times with an ultrasonic cleaner for an hour to soften the connective tissue around the nerve bundles. The spinal root origins of this communicating branch were found to be largely C7 and some C8. Unexpectedly, the branches of the ulnar nerve innervated the medial two-third of the medial head of the triceps brachii muscle on the right side in the same cadaver. Numbers of nerve fibers of the communicating branch and the main distributing branch of the ulnar nerve to the triceps brachii muscle were 523 and 525, respectively. This result implies that nerve fibers moving from the radial to the ulnar nerves may innervate the original distributing territories of the radial nerve. Another possibility is that a part of radial muscular branch to the triceps beachii muscle may be fused to the ulnar nerve in their distributing territories.
Subject(s)
Axilla , Brachial Plexus , Cadaver , Connective Tissue , Head , Muscles , Nerve Fibers , Radial Nerve , Spinal Nerve Roots , Ulnar Nerve , UltrasonicsABSTRACT
This case report describes a variation in the course of the accessory meningeal artery relative to the mandibular nerve in the infratemporal fossa. An accessory meningeal artery running superficially to the posterior division of mandibular nerve was found bilaterally in the cadaver of a 95-year-old male. It was observed by a topographic examination followed by a detailed dissection. The accessory meningeal artery arose from the middle meningeal artery. It then passed upward and coursed superficial to the posterior division of the mandibular nerve before its division into the lingual and inferior alveolar nerves. The accessory meningeal artery subsequently ran deep and rostral to the anterior and posterior divisions of the mandibular nerve, respectively, before entering the foramen ovale. The variation in the course of the accessory meningeal artery described herein should be helpful for surgeons in approaches to the foramen ovale region and infratemporal fossa.
Subject(s)
Humans , Male , Cadaver , Foramen Ovale , Mandibular Nerve , Meningeal Arteries , RunningABSTRACT
Accessory muscles passing through Guyon's canal are common; the most common anomalous muscle at Guyon's canal is the accessory abductor digiti minimi muscle (AADM). The aim of this study was to demonstrate and describe the gross anatomy of an anatomic variant of the AADM relative to the surrounding structures. The AADM was found in the left forearm and hand of a 61-year-old male cadaver during dissection in a gross anatomy course. It was observed by focusing on the shape, the course, and its relationship with the surrounding structures. The AADM originated as muscle fibers from the antebrachial fascia. It coursed downward in the distal forearm and crossed the ulnar nerve and artery obliquely at Guyon's canal. The AADM narrowed and became a long tendon in the hypothenar region. The abductor digiti minimi muscle was partly attached to the tendon of the AADM, running along the tendon. The tendon of the AADM inserted into the ulnar side of head of the fifth metacarpal bone. The AADM was innervated by several twigs from the ulnar nerve. We reported herein another variant of the AADM at Guyon's canal, which may be helpful to surgeons performing diagnoses and surgical procedures.
Subject(s)
Humans , Male , Middle Aged , Anatomic Variation , Arteries , Cadaver , Fascia , Forearm , Hand , Head , Muscles , Running , Tendons , Ulnar NerveABSTRACT
This study aimed to confirm the presence of motor fibers in the cervical nerves distributing to the trapezius muscle. Thirteen cases were examined. Motor fibers were present in C3 in 7 of 9 cases (77.8%) and were absent in 2 of 9 cases (22.3%); the other 4 cases were damaged during dissection. C4 exhibited motor fibers in 9 of 10 cases (90.0%), whereas motor fibers were absent in 1 of 10 cases (10.0%); and 3 cases were damaged. The motor fibers in C3 were of medium size (57.1%; 4/7 cases), whereas those in C4 were large (44.4%; 4/9 cases). The average number of motor fibers in C3 and C4 were 114+/-112 and 219+/-167, respectively. These results show that C4 is more important in terms of the frequency and size of the cervical motor fibers distributing to the trapezius muscle.
Subject(s)
MusclesABSTRACT
This study aimed to confirm the presence of motor fibers in the cervical nerves distributing to the trapezius muscle. Thirteen cases were examined. Motor fibers were present in C3 in 7 of 9 cases (77.8%) and were absent in 2 of 9 cases (22.3%); the other 4 cases were damaged during dissection. C4 exhibited motor fibers in 9 of 10 cases (90.0%), whereas motor fibers were absent in 1 of 10 cases (10.0%); and 3 cases were damaged. The motor fibers in C3 were of medium size (57.1%; 4/7 cases), whereas those in C4 were large (44.4%; 4/9 cases). The average number of motor fibers in C3 and C4 were 114+/-112 and 219+/-167, respectively. These results show that C4 is more important in terms of the frequency and size of the cervical motor fibers distributing to the trapezius muscle.
Subject(s)
MusclesABSTRACT
This study was carried out to evaluate the quantity of the nerve fiber of the terminal branches of the typical brachial plexus in the 6 sides of the Korean adults. The dorsal scapular nerve, which is derived from ramus of the brachial plexus, was comprised of C5 and participating nerve fiber was 355+/-180. The long thoracic nerve was composed of C5, C6 and C7, and was mainly originated from C6, and participating nerve fiber was 743+/-346. The nerves, which are branched out from trunk, nerve to subclavius muscle was composed of C5 and participating quantity was 242+/-71. The suprascapular nerve was comprised of C5 and C6, and the nerve fiber was mainly derived from C5 (1,942+/-505). The nerve, which is originated from proximal portion of the cord, the lateral pectoral nerve was constituted of C5, C6 and C7. The main component was C7 as the 2,917+/-785 nerve fiber. The medial pectoral nerve was made with C8 and T1. The main component was C8 as the 964+/-430 nerve fiber. The upper subscapular nerve was derived from C5 and C6. The nerve fiber was 1,179+/-92 in C5, mainly participated. The Lower subscapular nerve was constituted of C5, C6 and C7. C6 was the main component and contributing nerve fiber was 1,070+/-390 in C6, principal component. The thoracodorsal nerve was formed by C6, C7 and C8. The chief component was C7, contributed of 2,335+/-324. The nerves, which are came out from the distal portion of the cord, musculocutaneous nerve was derived from the C5, C6 and C7. The C6 was principal component, and was joined with 4,009+/-1,883. The median nerve was contributed from C5 to T1. The chief component was C7 added with 9,651+/-2,663. The ulnar nerve was composed of C7, C8 and T1. The C8 was the main component comprised of 10,075+/-1,473. The medial brachial and antebrachial cutaneous nerves was constituted of C8 and T1. In the both nerves, the main component was T1 participated with 1,752+/-390, 3,080+/-1,140 respectively. The radial nerve was composed of C5 to T1. The C7 was principal component added with 7,958+/-2,333. The axillary nerve was made up C5 and C6. In the nerve, the both spinal segments were similarly participated to the nerve. This results could be applied for the injuries and neurotization procedure of the terminal nerves of the brachial plexus.
Subject(s)
Brachial Plexus , Median Nerve , Muscles , Musculocutaneous Nerve , Nerve Fibers , Nerve Transfer , Porphyrins , Radial Nerve , Spinal Nerves , Thoracic Nerves , Ulnar NerveABSTRACT
The purpose of this study was to classify the spinal nerve compositions of the terminal branches of the lumbosacral plexus, providing data of their participating quantities. Twenty-five sides of the lumbosacral plexus extracted from Korean adult cadavers were used in this study. The iliohypogastric nerve was mostly arisen from L1 (88.2%, thickness L1 0.7 mm). The ilioinguinal nerve was arisen from only L1 (100%, thickness L1 0.6 mm). The genitofemoral nerve was commonly arisen from L1 and L2 (62.5%, thickness L1 0.6 mm, L2 0.7 mm). The lateral femoral cutaneous nerve was classified into 4 types, and the most common type was that L2 and L3 composed this nerve (56.0%, thickness L2 0.8 mm, L3 0.4 mm). The femoral nerve was classified into 2 types, and it was usually composed of L2, L3 and L4 (88.0%, thickness L2 1.4 mm, L3 2.7 mm, L4 2.3 mm). The obturator nerve was arisen from L2, L3 and L4 in all cases (100%, thickness L2 0.5 mm, L3 1.3 mm, L4 1.1 mm). The common fibular component of sciatic nerve was mostly arisen from L4, L5, S1 and S2 (84.0%, thickness L4 0.9 mm, L5 2.0 mm, S1 2.1 mm, S2 1.2 mm). The tibial component of sciatic nerve was mainly arisen from L4, L5, S1 and S2 (96.0%, thickness L4 0.9 mm, L5 1.9 mm, S1 2.2 mm, S2 1.9 mm). The superior gluteal nerve was commonly derived from L4, L5 and S1 (56.0%, thickness L4 0.7 mm, L5 1.1 mm, S1 0.9 mm). The inferior gluteal nerve was comprised of L5, S1 and S2 in several cases (54.2%, thickness L5 0.9 mm, S1 1.3 mm, S2 0.8 mm). The posterior femoral cutaneous nerve was composed of S1 and S2 in higher freqeuncy (40.0%, thickness S1 0.9 mm, S2 1.0 mm, S3 0.8 mm). The perforating cutaneous nerve was arisen from S2 and S3 in higher frequency (56.0%, thickness S1 0.7 mm, S2 0.9 mm, S3 1.1 mm). The pudendal nerve was derived from S3 in many cases (52.9%, thickness S3 1.5 mm). These anatomical results may be helpful to predict the spinal nerve root lesions of the lumbosacral plexus.