Regions of the lower limb
Regions of the lower limb
Muscles of the lower limb
The region behind the hip joint is composed of three gluteal muscles and five muscles which
overlie the pelvis.
Gluteus maximus is the most superficial muscle of the gluteal region. It is a large flat quadrilateral mass forming the prominence of the buttock.
- Origin: an extensive area of the gluteal surface of the ala of ilium behind the posterior gluteal line, posterior superior iliac spine and the posterior surfaces of the sacrum, coccyx and sacrotuberous ligament
- Insertion: the iliotibial tract and the gluteal tuberosity of the femur.
- Action: a powerful lateral rotator and extensor at the hip joint and acting through the iliotibial tract, it extends and stabilizes the hip joint and knee joint. It acts like an adductor (when inserted on the gluteal tuberosity) and like an abductor (when inserted on the fascia lata)
- Nerves: the inferior gluteal nerve (L5-S2)
The deep relation of this muscle:
It lies behind the hip joint and overlies the gluteus medius, the obturator internus
tendon – with the two gemelli, the quadratus femoris, the ischial attachments of
the hamstrings, and the structures passing through the greater and lesser sciatic
foramina.
- O: the gluteal surface of the ala of ilium between the anterior and posterior gluteal lines
- I: an oblique ridge on the lateral surface of the greater trochanter.
- V: the strongest abductor of the hip joint, anterior part – flexion and medial rotation of the hip joint, posterior part – extention and lateral rotation of the hip joint
- N: the superior gluteal nerve (L4-L5)
Gluteus minimus is the deepest of the gluteal muscles and is covered completely by gluteus medius.
- O: gluteal surface of the ala of ilium between the anterior and inferior
- gluteal lines
- I: anterior border of the greater trochanter.
- V: abduction of the hip joint, anterior part – functions as flexor and medial rotator of the hip joint, posterior part – extension and lateral rotation of the hip joint
- N: the superior gluteal nerve (L4-S1)
Piriformis passes laterally through the greater sciatic foramen.
O: the pelvic surface of the sacrum, lateral to the anterior sacral foramina (II-IV)
I: the upper border of the greater trochanter of the femur
A: rotates thigh laterally, abducts and extends
N: direct branches from the sacral plexus
Piriformis (musculus piriformis) passes laterally through the greater sciatic foramen
- O: the pelvic surface of the sacrum, lateral to the anterior sacral foramina (II-IV)
- I: the upper border of the greater trochanter of the femur
- A: rotates thigh laterally, abducts and extends
- N: direct branches from the sacral plexus
The gemelli are two small muscles which lie above and below the obturator internus tendon as it emerges from the lesser sciatic foramen. Medially they are attached to the ischium and laterally merge with the obturator internus tendon.
- Superior gemellus
- O: the ischial spine
- I: the trochanteric fossa (the obturator internus tendon)
- A: rotates thigh laterally, assist the obturator internus
- I: branch of the sacral plexus (L4(5)-S2), nerve to obturator internus
- Inferior gemellus
- O: the ischial tuberosity
- I: the trochanteric fossa (the obturator internus tendon)
- A: rotates thigh laterally and adducts, assist the obturator internus
- I: branch of the nerve to quadratus femoris (sacral plexus).
Obturator internus (musculus obturator internus) is a layer of muscular fibres converges on the lesser sciatic foramen and groove of the ischium and it turns laterally to leave the pelvis.
- O: pelvic surface of the obturator membrane and the ischiopubic ramus
- I: the trochanteric fossa (medial surface of the greater trochanter )
- A: adducts and rotates thigh laterally
- I: nerve to obturator internus, branch of the sacral plexus (L4(5)-S2)
Obturator externus is a short articular muscle, which lies close to the hip joint, above the adductor brevis. It passes from the outer surface of the obturator membrane and the adjacent bone and its tendon winds below and behind the hip joint to reach a pit on the medial surface of the greater trochanter.
- O: margin of the obturator foramen and obturator membrane
- I: intertrochanteric fossa
- A: it supports and stabilises the hip joint and is a weak lateral rotator of the femur
- N: obturator nerve
All muscles, which form the iliopsoas, insert into the region of the lesser trochanter. The
iliopsoas is a very important muscle because it is a very strong flexor and lateral rotator of the hip joint. The iliopsoas makes walking and running possible.
Iliopsoas is divided into:
There are 3 muscles in the anterior compartment of thigh or extensor compartment of thigh.
All muscles are supplied by femoral nerve:
Muscles of the posterior group of the thigh
Innervation of muscles of thigh – trasverse section.
The adductor group of muscles is arranged in three vertical layers; anteriorly pectineus and adductor longus (lies in the same plane) in front of adductor brevis which separates them from the adductor magnus (posteriorly). Gracilis lies superficial to these on the medial side of the thigh. These muscles adduct the femur. In addition pectineus and adductor longus rotates laterally the femur (attached pubis & posterior aspect of the femur), the adductor magnus extends it and the pectineus also helps to flex the femur.
There is only 1 muscle in lateral or abductor compartment of thigh:
Tensor fasciae latae
O: the anterior quarter of the outer lip of the iliac crest, anterior superior iliac spine
I: lateral condyle of tibia, extends into the iliotibial tract distal to the greater trochanter
A: it extends and stabilises the knee joint and it flexes, rotates medially and abducts hip
joint. It press the head of femur into the acetabulum
N: the superior gluteal nerve (L4-L5)
The iliotibial tract is a broad thickening of the fascia lata passing from the outer lip of the iliac
crest to the anterolateral aspect of the proximal end of the tibia. The iliotibial tract receives the
attachments of the tensor fasciae latae and gluteus maximus and these muscles, acting through it,
extend and stabilise the knee joint.
The muscles of the leg are divided into anterior, lateral and posterior groups by the tibia, interosseous membrane, and anterior and posterior intermuscular septa which pass inwards from the thick investing deep fascia to the fibula. The anterior intermuscular septum passes to the anterior border of the fibula and separates the anterior (dorsiflexor) compartment from the lateral (peroneal) compartment. The posterior septum passes to the posterior border of the fibula and separates the lateral from the posterior (plantar flexor) compartment.
There are only two dorsal muscles of the foot: extensor digitorum brevis , and extensor hallucis brevis lie under tendons of the extensor digitorum longus muscle.
O: superior and lateral surfaces of the calcaneus
I: toes (I-IV), four tendons fuse with the lateral margin of the extensor digitorum longus and the
extensor hallucis longus. The 5th toe has the tendon from the peroneal tertius muscle.
A: extends metatarsophalangeal joints
N: deep peroneal nerve.
The plantar muscles consists of three groups which are divided into four layers. The muscles of
the sole of foot form the following groups:
REMEMBER!!! All plantar muscles which are innervated by lateral plantar nerve!!!
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Second toe Lumbrical
Flexor Hallucis brevis
Abductor Hallucis
Flexor Digitorum Brevis
Short flexors, abductors, and adductor of the big toe, lumbrical and interosseous muscles are present but there is no opponens muscle. The small muscles help to maintain the arches and move the toes but have little abductor or adductor action.
The flexor accessorius has no counterpart in the hand. It is attached to the calcaneus posteriorly and to the lateral side of the tendons of flexor digitorum longus and flexor hallucis longus anteriorly. Tension in the digital tendons and flexion of the toes can be maintained by accessorius when the long flexors have to relax. This occurs when the leg is being pulled forwards over the ankle joint by tibialis anterior and the extensor muscles during the supporting phase of walking.
All the short muscles of the sole are supplied by the lateral plantar nerve except for abductor hallucis, flexor hallucis brevis, flexor digitorum brevis and the 1 st lumbrical which are supplied by the medial plantar nerve.
The long flexor tendons pass along the sole of the foot into the flexor tendon sheaths and are attached to the base of the terminal phalanges. The tendons of three large muscles are inserted close together on the medial side of the foot. The tendon of tibialis posterior is attached to the tuberosity of the navicular and then spreads out to all the other tarsal bones except the talus and to some metatarsal bases. The tendon of peroneus longus, having crossed the foot, is attached to the lateral side of the medial cuneiform and of the 1 st metatarsal base. The tendon of tibialis anterior is attached to the medial side of the same two bones. These three muscles are strong supporters of the arches of the foot.
The plantar fascia consists of a thickened central portion, the plantar aponeurosis, and thin medial and lateral portions. The aponeurosis is attached posteriorly to the back of the undersurface of the calcaneus and divides anteriorly into five digital expansions. These are continuous with the fibrous flexor tendon sheaths along the plantar aspect of the toes, and are also attached to the ligaments binding together the heads of the metatarsals. When the toes are dorsiflexed, the plantar aponeurosis is tightened and the longitudinal arch is accentuated. There are transverse fasciculi and superficial transverse metatarsal ligaments between parts of plantar aponeurosis. There is dorsal fascia of foot on dorsal surface of foot.
Actions of the muscles
Nerves of the lumbo-sacral plexus
The lumbosacral plexus is formed by the ventral rami of the lumbar (L 1-5), sacral (S 1-5) spinal nerves and ventral ramus of coccygeal nerve (C0).
The terminal line of the pelvis separates this plexus into lumbar part (lumbar plexus) and sacral part (sacral plexus). The lumbosacral trunk joins two parts of the lumbosacral plexus. The lumbosacral trunk (ventral rami of 4th and 5th lumbar nerves) is this part of the lumbar nerves which descends medial to psoas over the sacrum to join the sacral part of the lumbosacral plexus, so the 4th ventral ramus gives fibres to the lumbar and sacral parts and is often termed nervus furcalis.
The lumbar part
The lumbar part is upper one of the lumbosacral plexus, which lies between two layers of the psoas major, anterior to the transverse processes of lumbar vertebrae.
The lumbar plexus gives the following branches:
The muscular branches supply the quadratus lumborum psoas major, minor and iliacus
muscles.
The iliohypogastric nerve pass laterally around posterior abdominal wall, it pierces the transversus abdominis to run on the posterior surface of the internal oblique muscle. It supplies these muscles and skin above the pubis and gluteal region.
The ilioinguinal nerve pass laterally and pierces transversus abdominis and internal oblique muscle to run on the posterior surface of the external oblique muscle, it traverse the inguinal canal beneath spermatic cord or round ligament, emerging from superficial ring. It supplies these muscles and skin the genitalia by anterior scrotal or anterior labial branches.
The genitofemoral nerve descends on the anterior surface of the psoas. It gives:
The lateral femoral cutaneous nerve descends on iliacus to enter the thigh deep to the lateral
end of the inguinal ligament. It supplies the parietal peritoneum of the iliac fossa and the
lateral region of the thigh.
The obturator nerve is a branch (L2,3,4) descends in the pelvis medial (!) to the psoas major and runs along the lateral wall of the obturator canal through which it passes to reach the thigh. It passes between the internal iliac vessels and the lateral pelvic wall above the obturator artery. In female the obturator nerve lies lateral to the ovary. It gives no branches in the pelvis. It enters the thigh through the obturator groove where it divides into:
The femoral nerve (L2, L3, L4) descends in the pelvis in the groove between psoas and iliacus, and enters the thigh deep to the inguinal ligament. Here it lies on iliacus lateral to the femoral artery. After a short course, it divides into a number of terminal branches which are separated into superficial and deep groups by the lateral circumflex femoral artery.
It gives the following branches:
The sacral part
The sacral part is lower one of the lumbosacral plexus and consists of the ventral rami of the 4th and 5th lumbar nerves (!), and all ventral rami of sacral nerves together with ventral ramus of the coccygeal nerve. It lies on the pelvic surface of the sacrum in the front of the piriformis.
Its branches are divided into groups:
Relations of the sciatic nerve on entering the gluteal region.
- below piriformis.
- medially – the inferior gluteal vessels and nerve.
- anteriorly – the posterior cutaneous nerve of thigh posteriorly and the nerve to quadratus femoris between it and the ischium. Anteriorly the nerve lies on the ischium, obturator internus and the gemelli, quadratus femoris and adductor magnus from above downwards.
- covered posteriorly by gluteus maximus and the hamstring muscles.
It gives the following branches:
- articular – to the hip joint.
- muscular – to the hamstrings and the ischial part of adductor magnus.
- tibial and common peroneal nerves.
Skin innervation of the thigh
Vessels of the thigh
This begins at the opening in the lower end of adductor magnus as the continuation of the popliteal vein. It accompanies the femoral artery and ends at the level of the inguinal ligament by becoming the external iliac vein. In its lower part it is located posterolateral to the artery but as it ascends it passes behind, and ends on its medial side.
Tributaries:
Fasciae
Topographical elements of the thigh
Vessels and nerves of the leg
Plantar vessels
Plantar nerves
Topographical elements of the foot
On the lower limb the peripheral pulse may be felt at the following pulse points:
- Femoral artery
- Popliteal artery
- Posterior tibial artery
- Dorsalis pedis artery