MSK Session 6 - Hip Flashcards
Describe the structure and function of the hip joint.
- The hip joint is a ball and socket synovial joint, formed by an articulation between the pelvic acetabulum and the head of the femur.
- It forms a connection from the lower limb to the pelvic girdle, and thus is designed for stability and weight-bearing – rather than a large range of movement.
Describe the articulating surfaces of the hip joint.
- The hip joint consists of an articulation between the head of femur and acetabulum of the pelvis.
- The acetabulum is a cup-like depression located on the inferolateral aspect of the pelvis. Its cavity is deepened by the presence of a fibrocartilaginous collar – the acetabular labrum. The head of femur is hemispherical, and fits completely into the concavity of the acetabulum.
- Both the acetabulum and head of femur are covered in articular cartilage, which is thicker at the places of weight bearing.
Identify the vascular structures associated with the hip joint
- The arterial supply to the hip joint is largely via the medial and lateral circumflex femoral arteries – branches of the profunda femoris artery (deep femoral artery). They anastomose at the base of the femoral neck to form a ring, from which smaller arteries arise to supply the hip joint itself.
- The medial circumflex femoral artery is responsible for the majority of the arterial supply (the lateral circumflex femoral artery has to penetrate through the thick iliofemoral ligament). Damage to the medial circumflex femoral artery can result in avascular necrosis of the femoral head.
- The artery to head of femur and the superior/inferior gluteal arteries provide some additional supply.
Identify the nervous structures associated with the hip joint
The hip joint is innervated by the femoral nerve, obturator nerve, superior gluteal nerve, and nerve to quadratus femoris.
The ligaments of the hip joint act to increase stability. They can be divided into two groups – intracapsular and extracapsular. Outline the structure and function of the intracapsular ligaments.
- The only intracapsular ligament is the ligament of head of femur.
- It is a relatively small structure, which runs from the acetabular fossa to the fovea of the femur.
- It encloses a branch of the obturator artery (artery to head of femur), a minor source of arterial supply to the hip joint.
The ligaments of the hip joint act to increase stability. They can be divided into two groups – intracapsular and extracapsular. Outline the structure and function of the extracapsular ligaments.
There are three main extracapsular ligaments, continuous with the outer surface of the hip joint capsule:
- Iliofemoral ligament – spans between the anterior inferior iliac spine and the intertrochanteric line of the femur. It has a ‘Y’ shaped appearance, and prevents hyperextension of the hip joint
- Pubofemoral – spans between the superior pubic rami and the intertrochanteric line of the femur. It has a triangular shape, and prevents excessive abduction and extension.
- Ischiofemoral – spans between the body of the ischium and the greater trochanter of the femur. It has a spiral orientation, and prevents excessive extension.
Describe the factors that stabilise the hip joint
- There are a number of factors that act to increase stability of the joint.
- The first structure is the acetabulum. It is deep, and encompasses nearly all of the head of the femur. This decreases the probability of the head slipping out of the acetabulum (dislocation).
- There is a fibrocartilaginous collar around the acetabulum which increases its depth, known as the acetabular labrum. The increase in depth provides a larger articular surface, further improving the stability of the joint.
- The iliofemoral, pubofemoral and ischiofemoral ligaments are very strong, and along with the thickened joint capsule, provide a large degree of stability.
- These ligaments have a unique spiral orientation; this causes them to become tighter when the joint is extended.
The muscles and ligaments work in a reciprocal fashion at the hip joint. Explain this.
- Anteriorly, where the ligaments are strongest, the medial flexors (located anteriorly) are fewer and weaker.
- Posteriorly, where the ligaments are weakest, the medial rotators are greater in number and stronger – they effectively ‘pull’ the head of the femur into the acetabulum.
Identify the muscles which produce movement at the hip joint.
The movements that can be carried out at the hip joint are listed below, along with the principle muscles responsible for each action:
- Flexion – iliopsoas, rectus femoris, Sartorius
- Extension – gluteus maximus, semimembranosus, semitendinosus and biceps femoris
- Abduction – gluteus medius, gluteus minimus and the deep gluteals (piriformis, gemelli etc.)
- Adduction – adductors longus, brevis and magnus, pectineus and gracillis
- Lateral rotation – biceps femoris, gluteus maximus, and the deep gluteals (piriformis, gemelli etc.)
- Medial rotation – gluteus medius and minimus, semitendinosus and semimembranosus
Describe extension and flexion at the hip joint.
- The degree to which flexion at the hip can occur depends on whether the knee is flexed – this relaxes the hamstring muscles, and increases the range of flexion.
- Extension at the hip joint is limited by the joint capsule and the iliofemoral ligament.
- These structures become taut during extension to limit further movement.
What is the lumbar plexus?
- The lumbar plexus is a network of nerve fibres that supplies the skin and musculature of the lower limb.
- It is located in the lumbar region, within the substance of the psoas major muscle and anterior to the transverse processes of the lumbar vertebrae.
Describe the properties of the anterior rami of the lumbar plexus.
- The plexus is formed by the anterior rami (divisions) of the lumbar spinal nerves L1, L2, L3 and L4. It also receives contributions from thoracic spinal nerve 12.
- The anterior rami of the L1-L4 spinal roots divide into several cords.
- These cords then combine together to form the six major peripheral nerves of the lumbar plexus.
- These nerves then descend down the posterior abdominal wall to reach the lower limb, where they innervate their target structures.
Outline the structure, roots, motor and sensory functions of the iliohypogastric nerve.
- Structure: The iliohypogastric nerve is the first major branch of the lumbar plexus. It runs to the iliac crest, across the quadratus lumborum muscle of the posterior abdominal wall. It then perforates the transversus abdominis, and divides into its terminal branches.
- Roots: L1 (with contributions from T12).
- Motor Functions: Innervates the internal oblique and transversus abdominis.
- Sensory Functions: Innervates the posterolateral gluteal skin in the pubic region
Outline the structure, roots, motor and sensory functions of the Ilioinguinal nerve.
- Structure: The ilioinguinal nerve follows the same anatomical course as the larger iliohypogastric nerve. After innervating the muscles of the anterior abdominal wall, it passes through the superficial inguinal ring to innervate the skin of the genitalia and middle thigh.
- Roots: L1.
- Motor Functions: Innervates the internal oblique and transversus abdominis.
- Sensory Functions: Innervates the skin on the upper middle thigh. In males, it also supplies the skin over the root of the penis and anterior scrotum. In females, it supplies the skin over mons pubis and labia majora.
Outline the structure, roots, motor and sensory functions of the genitofemoral nerve.
- Structure: After leaving the psoas major muscle, the genitofemoral nerve quickly divides into a genital branch, and a femoral branch.
- Roots: L1, L2.
- Motor Functions: The genital branch innervates the cremasteric muscle.
- Sensory Functions: The genital branch innervates the skin of the anterior scrotum (in males) or the skin over mons pubis and labia majora (in females). The femoral branch innervates the skin on the upper anterior thigh.
Outline the structure, roots, motor and sensory functions of the lateral cutaneous nerve of the thigh.
- Structure: This nerve has a purely sensory function. It enters the thigh at the lateral aspect of the inguinal ligament, where it provides cutaneous innervation to the skin there.
- Roots: L2, L3
- Motor Functions: None.
- Sensory Functions: Innervates the anterior and lateral thigh down to the level of the knee
Outline the roots, motor and sensory functions of the obturator nerve
- Roots: L2, L3, L4.
- Motor Functions: Innervates the muscles: obturator externus, pectineus, adductor longus, adductor brevis, adductor magnus, gracilis.
- Sensory Functions: Innervates the skin over the medial thigh.
Outline the roots, motor and sensory functions of the femoral nerve
- Roots: L2, L3, L4.
- Motor Functions: Innervates the muscles: Illiacus, pectineus, sartorius, all the muscles of quadriceps femoris.
- Sensory Functions: Innervates the skin on the anterior thigh and the medial leg.
Outline the structure and properties of the sacral plexus.
- The sacral plexus is a network of nerve fibres that supplies the skin and muscles of the pelvis and lower limb. It is located on the surface of the posterior pelvic wall, anterior to the piriformis muscle.
- The plexus is formed by the anterior rami (divisions) of the sacral spinal nerves S1, S2, S3 and S4. It also receives contributions from the lumbar spinal nerves L4 and L5.
- At each vertebral level, paired spinal nerves leave the spinal cord via the intervertebral foramina of the vertebral column.
- Each nerve then divides into anterior and posterior nerve fibres.
- The sacral plexus begins as the anterior fibres of the spinal nerves S1, S2, S3, and S4.
- They are joined by the 4th and 5th lumbar roots, which combine to form the lumbosacral trunk.
- This descends into the pelvis to meet the sacral roots as they emerge from the spinal cord.
Outline the structure, roots, motor and sensory functions of the superior gluteal nerve.
- Structure: The superior gluteal nerve leaves the pelvis via the greater sciatic foramen, entering the gluteal region superiorly to the piriformis muscle. It is accompanied by the superior gluteal artery and vein for much of its course.
- Roots: L4, L5, S1.
- Motor Functions: Innervates the gluteus minimus, gluteus medius and tensor fascia lata.
- Sensory Functions: None.
Outline the structure, roots, motor and sensory functions of the inferior gluteal nerve.
- Structure: The inferior gluteal nerve leaves the pelvis via the greater sciatic foramen, entering the gluteal region inferiorly to the piriformis muscle. It is accompanied by the inferior gluteal artery and vein for much of its course.
- Roots: L5, S1, S2.
- Motor Functions: Innervates gluteus maximus.
- Sensory Functions: None.
Outline the roots, motor and sensory functions of the sciatic nerve.
- Roots: L4, L5, S1, S2, S3
- Motor Functions:
I. Tibial Portion – Innervates all of the muscles in the posterior compartment of the thigh, including the hamstring portion of adductor magnus, apart from the short head of the biceps femoris. All muscles in the posterior compartment of the leg. All muscles in the sole of the foot.
ii. Common Fibular Portion – Short head of biceps femoris, all muscles in the anterior and lateral compartments of the leg and extensor digitorum brevis.
- Sensory Functions:
I. Tibial Portion: Innervates the skin on the posterolateral and medial surfaces of the foot as well as the sole of the foot.
II. Common Fibular Portion: Innervates the skin on the anterolateral surface of the leg and the dorsal aspect of the foot.
Outline the structure, roots, motor and sensory functions of the posterior femoral nerve.
- Structure: The posterior cutaneous nerve of thigh leaves the pelvis via the greater sciatic foramen, entering the gluteal region inferiorly to the piriformis muscle. It descends deep to the gluteus maximus and runs down the back of the thigh to the knee.
- Roots: S1, S2, S3
- Motor Functions: None
- Sensory Functions: Innervates the skin on the posterior surface of the thigh and leg. Also, innervates the skin of the perineum.
Outline the structure, roots, motor and sensory functions of the pudendal nerve.
- Structure: This nerve leaves the pelvis via the greater sciatic foramen, then re-enters via the lesser sciatic foramen. It moves anterosuperiorly along the lateral wall of the ischiorectal fossa, and terminates by dividing into several branches.
- Roots: S2, S3, S4
- Motor Functions: Innervates the skeletal muscles in the perineum, the external urethral sphincter, the external anal sphincter, levator ani.
- Sensory Functions: Innervates the penis and the clitoris and most of the skin of the perineum.
Outline the anatomical course of the femoral nerve.
- The femoral nerve is the largest branch of the lumbar plexus. It is derived from the nerve roots L2 – L4.
- The nerve descends from the lumbar plexus in the abdomen through the psoas major muscle. The nerve then travels through the pelvis to approximately the mid-point of the inguinal ligament. It then traverses behind the inguinal ligament into the thigh and splits into an anterior and posterior division.
- It passes through the femoral triangle lateral to the femoral vessels (enclosed within the femoral sheath) and gives off articular branches to the hip and knee joints.
- The terminal cutaneous branch of the femoral nerve is the saphenous nerve which continues, with the femoral artery and vein, through the adductor canal
Outline the motor functions of the femoral nerve in line of hip flexors and knee extensors.
- The femoral nerve supplies some of the muscles of the anterior thigh
- Hip Flexors
I. Pectineus – adducts and flexes the thigh, assists with medial rotation of the thigh.
II. Iliacus – acts with psoas major and psoas minor (forming iliopsoas) to flex the thigh at the hip joint and stabilise the hip joint.
III. Sartorius – flexes, abducts and laterally rotates the thigh at the hip joint. Flexes the leg at the knee joint.
- Knee Extensors
Quadriceps femoris (rectus femoris, vastus lateralis, vastus intermedius) – extends the leg at the knee joint. Rectus femoris also steadies the hip joint and assists iliopsoas in flexing the thigh.
Outline the sensory functions of the femoral nerve.
The first cutaneous branches of the femoral nerve are the anterior cutaneous branches that arise in the femoral triangle. They supply the skin on the anteromedial thigh.
- The last cutaneous branch of the femoral nerve is the saphenous nerve which supplies the skin on the medial side of the leg and the foot.
Describe the anatomical course of the obturator nerve.
- The obturator nerve is formed by the anterior divisions of the second, third and fourth lumbar nerves.
- It descends through the fibres of the psoas major muscle and emerges from its medial border, running posteriorly to the common iliac arteries and laterally along the pelvic wall to the obturator foramen. It then enters the thigh through the obturator canal and splits into anterior and posterior divisions.
- The anterior division descends between the adductor longus and adductor brevis muscles towards the femoral artery, giving off branches to the adductor longus, adductor brevis and gracilis muscles. In rare cases it also gives off a branch to the pectineus muscle. It then pierces the fascia lata to become the cutaneous branch of the obturator nerve.
- The posterior division descends through the obturator externus muscle before passing anteriorly to adductor magnus and giving off branches to supply it.
Outline the motor functions of the obturator nerve.
- The obturator nerve innervates all the muscles in the medial compartment of the thigh except the hamstring part of the adductor magnus, which is innervated by the tibial nerve.
- Adductor Longus – adducts thigh
- Adductor Brevis – adducts thigh
- Adductor Magnus – adductor part adducts and flexes thigh, hamstring part extends thigh
- Gracilis – adducts thigh
- Obturator Externus – laterally rotates thigh
Outline the sensory functions of the obturator nerve.
The cutaneous branch of the obturator nerve supplies the skin of the middle part of the medial thigh.
Describe the anatomical course of the sciatic nerve.
- The sciatic nerve is derived from the lumbosacral plexus. After its formation, it leaves the pelvis and enters the gluteal region via greater sciatic foramen. It emerges inferiorly to the piriformis muscle and descends in an inferolateral direction.
- As the nerve moves through the gluteal region, it crosses the posterior surface of the superior gemellus, obturator internus, inferior gemellus and quadratus femoris muscles. It then enters the posterior thigh by passing deep to the long head of the biceps femoris.
- Within the posterior thigh, the nerve gives rise to branches to the hamstring muscles and adductor magnus. When the sciatic nerve reaches the apex of the popliteal fossa, it terminates by bifurcating into the tibial and common fibular nerves.
Outline the motor functions of the sciatic nerve.
- Although the sciatic nerve passes through the gluteal region, it does not innervate any muscles there. However, the sciatic nerve does directly innervate the muscles in the posterior compartment of the thigh, and the hamstring portion of the adductor magnus.
- The sciatic nerve also indirectly innervates several other muscles, via its two terminal branches:
I. Tibial nerve – the muscles of the posterior leg (calf muscles), and some of the intrinsic muscles of the foot.
II. Common fibular nerve – the muscles of the anterior leg, lateral leg, and the remaining intrinsic foot muscles.
- In total, the sciatic nerve innervates the muscles of the posterior thigh, entire leg and entire foot.
Outline the sensory functions of the sciatic nerve.
- The sciatic nerve does not have any direct cutaneous functions. It does provide indirect sensory innervation via its terminal branches:
- Tibial nerve – Innervates the posterolateral and anterolateral sides of the leg, and the plantar surface of the foot (the sole).
- Common fibular nerve – Innervates the lateral leg and the dorsal surface of the foot.
Outline the properties of the fascia lata.
Fascia is defined as a sheet or band of fibrous tissue lying deep to the skin that lines, invests and separates structures within the body. There are three general classifications of fascia:
- Superficial fascia: blends with the reticular layer beneath the dermis.
- Deep fascia: envelopes muscles, bones and neurovascular structures.
- Visceral fascia: provides membranous investments that suspend organs within their cavities.
Describe the anatomical structure of the fascia lata.
- The fascia lata is a deep fascial investment of the whole thigh musculature and is analogous to a strong, extensible and elasticated stocking.
- It begins most proximally around the iliac crest and inguinal ligamentand ends most distally to the bony prominences of the tibia; where it continues to become the deep fascia of the leg (the crural fascia).
Describe the width of the fascia lata.
- The width of the fascia lata varies considerably at different regions of the thigh.
- It is thickest along the superolateral aspect of the thigh, originating from the fascial condensations from gluteus maximus and medius, and also from around the knee where the fascia receives reinforcing fibres from tendons.
- The fascial investment is thinnest where it covers theadductor muscles of the medial thigh.
Describe the septa and divisions of the fascia lata.
- The deepest aspect of fascia lata gives rise to threeintermuscular septa that attach centrally to the femur.
- This divides the thigh musculature into three compartments; anterior, medial and lateral.
- The lateral intermuscular septum is the strongest of the three due to reinforcement from the iliotibial tract(see later), whereas the other two septa are proportionately weaker.
Outline the importance of the saphenous opening in the fascia lata.
- An ovoid hiatus is present in the fascia lata just inferior to the inguinal ligament known as the saphenous opening.
- This gap serves as an entry point for efferent lymphatic vessels and the great saphenous vein, draining into superficial inguinal lymph nodes and the femoral vein respectively.
- A covering of membranous tissue (the cribriform fascia) covers the hiatus which develops inferomedially from a sharp margin of the gap (the falciform margin).
What is the Tensor Fascia Lata (TFL)?
The tensor fascia lata is a gluteal muscle that acts as a flexor, abductor and internal rotator of the hip. Its nomenclature however, is derived from its additional role in tensing the fascia lata.
What are the origins and insertions of the TFL?
- The muscle originates from the iliac crest, and descends down the superolateral thigh.
- At the junction of the middle and upper thirds of the thigh, it inserts into the anterior aspect of the iliotibial tract.
- When stimulated, the tensor fasciae lata tautens the iliotibial band and braces the knee, especially when the opposite foot is lifted.
The superficial muscles in the gluteal region consist of the three glutei and the tensor fascia lata. They mainly act to abduct and extend the lower limb at the hip joint.
Outline the structure, attachments, actions and innervation of the gluteus maximus.
- Structure: The gluteus maximus is the largest of the gluteal muscles. It is also the most superficial, producing the shape of the buttocks.
- Attachments: Originates from the gluteal (posterior) surface of the ilium, sacrum and coccyx. It slopes across the buttock at a 45 degree angle, then inserts into the iliotibial tract and the gluteal tuberosity of the femur.
- Actions: It is the main extensor of the thigh, and assists with lateral rotation. However, it is only used when force is required, such as running or climbing.
- Innervation: Inferior gluteal nerve.
The superficial muscles in the gluteal region consist of the three glutei and the tensor fascia lata. They mainly act to abduct and extend the lower limb at the hip joint.
Outline the structure, attachments, actions and innervation of the gluteus medius.
- Structure:The gluteus medius muscle is fan-shaped and lies between to the gluteus maximus and the minimus. It is similar is shape and function to the gluteus minimus.
- Attachments: Originates from the gluteal surface of the ilium and inserts into the lateral surface of the greater trochanter.
- Actions: Abducts and medially rotates the lower limb. During locomotion, it secures the pelvis, preventing pelvic drop of the opposite limb. (Note: the posterior fibres of the gluteus medius are also thought to produce a small amount of lateral rotation).
- Innervation: Superior gluteal nerve.
The superficial muscles in the gluteal region consist of the three glutei and the tensor fascia lata. They mainly act to abduct and extend the lower limb at the hip joint.
Outline the structure, attachments, actions and innervation of the gluteus minimus.
- Structure: The gluteus minimus is the deepest and smallest of the superficial gluteal muscles. It is similar is shape and function to the gluteus medius.
- Attachments: Originates from the ilium and converges to form a tendon, inserting to the anterior side of the greater trochanter.
- Actions: Abducts and medially rotates the lower limb. During locomotion, it secures the pelvis, preventing pelvic drop of the opposite limb.
- Innervation: Superior gluteal nerve.
Outline the structure, attachments, actions and innervation of the piriformis.
- Structure: The piriformis muscle is a key landmark in the gluteal region. It is the most superior of the deep muscles.
- Attachments: Originates from the anterior surface of the sacrum. It then travels infero-laterally, through the greater sciatic foramen, to insert into the greater trochanter of the femur.
- Actions: Lateral rotation and abduction.
- Innervation: Nerve to piriformis.
Outline the structure, attachments, actions and innervation of the obturator internus.
- Structure: The obturator internus forms the lateral walls of the pelvic cavity. In some texts, the obturator internus and the gemelli muscles are considered as one muscle – the triceps coxae.
- Attachments: Originates from the pubis and ischium at the obturator foramen. It travels through the lesser sciatic foramen, and attaches to the greater trochanter of the femur.
- Actions: Lateral rotation and abduction.
- Innervation: Nerve to obturator internus.
Outline the structure, attachments, actions and innervation of the gemelli.
- Structure: The gemelli are two narrow and triangular muscles. They are separated by the obturator internus tendon.
- Attachments: The superior gemellus muscle originates from the ischial spine, the inferior from the ischial tuberosity. They both attach to the greater trochanter of the femur.
- Actions: Lateral rotation and abduction.
- Innervation: The superior gemellus muscle is innervated by the nerve to obturator internus, the inferior gemellus is innervated by the nerve to quadratus femoris.
Outline the structure, attachments, actions and innervation of the quadrator femoris.
- Structure: The quadratus femoris is a flat, square-shaped muscle. It is the most inferior of the deep gluteal muscles, located below the gemelli and obturator internus.
- Attachments: It originates from the lateral side of the ischial tuberosity, and attaches to the quadrate tuberosity on the intertrochanteric crest.
- Actions: Lateral rotation.
- Innervation: Nerve to quadratus femoris.
Outline the structure, attachments, actions and innervations of the biceps femoris.
- Structure: Like the biceps brachii in the arm, the biceps femoris muscle has two heads – a long head and a short head. It is the most lateral of the muscles in the posterior thigh – the common tendon of the two heads can be felt laterally at the posterior knee.
- Attachments: The long head originates from the ischial tuberosity of the pelvis. The short head originates from the linea aspera on posterior surface of the femur. Together, the heads form a tendon, which inserts into the head of the fibula.
- Actions: Main action is flexion at the knee. It also extends the leg at the hip, and laterally rotates at the hip and knee.
- Innervation: Long head innervated by the tibial part of the sciatic nerve, whereas the short head is innervated by the common fibular part of the sciatic nerve.
Outline the structure, attachments, actions and innervations of the semitendinosus.
- Structure: The semitendinosus is a largely tendinous muscle. It lies medially to the biceps femoris, and covers the majority of the semimembranosus.
- Attachments: It originates from the ischial tuberosity of the pelvis, and attaches to the medial surface of the tibia.
- Actions: Flexion of the leg at the knee joint. Extension of thigh at the hip. Medially rotates the thigh at the hip joint and the leg at the knee joint.
- Innervation: Tibial part of the sciatic nerve.
Outline the structure, attachments, actions and innervations of the semimembranosus.
- Structure: The semimembranosus muscle is flattened and broad, located underneath the semitendinosus.
- Attachments: It originates from the ischial tuberosity, but does so more superiorly than the semitendinosus and biceps femoris. It attaches to the medial tibial condyle.
- Actions: Flexion of the leg at the knee joint. Extension of thigh at the hip. Medially rotates the thigh at the hip joint and the leg at the knee joint.
- Innervation: Tibial part of the sciatic nerve.
The popliteal fossa is diamond shaped, with four borders. These borders are formed by the muscles in the posterior compartment of the leg and thigh. Identify them.
- Superomedial border: Semimembranosus.
- Superolateral border: Biceps femoris.
- Inferomedial border: Medial head of the gastrocnemius.
- Inferolateral border: Lateral head of the gastrocnemius and plantaris.
The popliteal fossa is the main conduit for neurovascular structures entering and leaving the leg. Outline its contents.
- Its contents are (medial to lateral):
I. Popliteal artery
II. Popliteal vein
III. Tibial nerve
IV. Common fibular nerve
- The tibial and common fibular nerves are the most superficial of the contents of the popliteal fossa. They are both branches of the sciatic nerve. The common fibular nerve follows the biceps femoris tendon, running along the lateral margin of the popliteal fossa.
- The small saphenous vein pierces the popliteal fascia of the popliteal fossa to enter the diamond, and empty into the popliteal vein.
- In the popliteal fossa, the deepest structure is the popliteal artery. It is a continuation of the femoral artery, and travels into the leg to supply it with blood
Describe the arterial supply of the gluteal region.
- The gluteal region is largely supplied by the superior and inferior gluteal arteries. These arteries also arise from the internal iliac artery, entering the gluteal region via the greater sciatic foramen.
- The superior gluteal artery leaves the foramen above the piriformis muscle, the inferior below the muscle. In addition to the gluteal muscles, the inferior gluteal artery also contributes towards the vasculature of the posterior thigh.
Outline the supply of the popliteal artery.
- The popliteal artery descends down the posterior thigh, giving off genicular branches that supply the knee joint.
- It moves through the popliteal fossa, exiting sandwiched between the gastrocnemius and popliteus muscles.
- At the lower border of the popliteus, the popliteal artery terminates by dividing into anterior and posterior tibial arteries.
Outline the anatomical course of the posterior tibial artery.
- The posterior tibial artery continues inferiorly, along the surface of the deep muscles (such as tibialis posterior).
- It accompanies the tibial nerve in entering the sole of the foot via the tarsal tunnel.
- During the descent of the posterior tibial artery in the leg, the fibular artery arises.
- This artery moves laterally, penetrating the lateral compartment of the leg.
- It supplies muscles in the lateral compartment, and adjacent muscles in the posterior compartment.
Describe the anatomical course of the anterior tibial artery.
- The other division of the popliteal artery, the anterior tibial artery, passes anteriorly between the tibia and fibula, through a gap in the interosseous membrane.
- It then moves inferiorly down the leg.
- It runs down the entire length of the leg, and into the foot, where it becomes the dorsalis pedis artery.
Outline the venous drainage of the foot and leg.
- The main venous structure of the foot is the dorsal venous arch, which mostly drains into the superficial veins. Some veins from the arch penetrate deep into the leg, forming the anterior tibial vein.
- On the plantar aspect of the foot, medial and lateral plantar veins arise. These veins combine to form the posterior tibial and fibular veins. The posterior tibial vein accompanies the posterior tibial artery, entering the leg posteriorly to the medial malleolus.
- On the posterior surface of the knee, the anterior tibial, posterior tibial and fibular veins unite to form the popliteal vein. The popliteal vein enters the thigh via the adductor canal.
Outline the venous drainage of the thigh.
- Once the popliteal vein has entered the thigh, it is known as the femoral vein. It is situated anteriorly, accompanying th e femoral artery.
- The deep vein of the thigh (profunda femoris vein) is the other main venous structure in the thigh. Via perforating veins, it drains blood from the thigh muscles. It then empties into the distal section of the femoral vein.
- The femoral vein leaves the thigh by running underneath the inguinal ligament, at which point it is known as the external iliac vein.
Outline the venous drainage of the gluteal region.
- The gluteal region is drained by inferior and superior gluteal veins.
- These empty into the internal iliac vein.
The superficial veins of the lower limb run in the subcutaneous tissue. There are two major superficial veins – the great saphenous vein, and the small saphenous vein. Outline the anatomical course of the great saphenous vein.
- The great saphenous vein is formed by the dorsal venous arch of the foot, and the dorsal vein of the great toe. It ascends up the medial side of the leg, passing anteriorly to the medial malleolus at the ankle, and posteriorly to the medial condyle at the knee.
- As the vein moves up the leg, it receives tributaries from other small superficial veins. The great saphenous vein terminates by draining into the femoral vein immediately inferior to the inguinal ligament.
- Surgically, the great saphenous vein can be harvested and used as a vessel in coronary artery bypasses.
The superficial veins of the lower limb run in the subcutaneous tissue. There are two major superficial veins – the great saphenous vein, and the small saphenous vein. Outline the anatomical course of the small saphenous vein.
- The small saphenous vein is formed by the dorsal venous arch of the foot, and the dorsal vein of the little toe.
- It moves up the posterior side of the leg, passing posteriorly to the lateral malleolus, along the lateral border of the calcaneal tendon.
- It moves between the two heads of the gastrocnemius muscle and empties into the popliteal vein in the popliteal fossa.
The inguinal nodes are found in the upper aspect of the femoral triangle and are 1—20 in number.
They are subdivided into 2 groupings determined by their position relative to a horizontal line drawn at the level of termination of the great saphenous vein.
Identify and outline them.
Those below this line are the sub-inguinal nodes (consisting of a deep and superficial set) and those above are the superficial inguinal nodes.
- Superficial Inguinal Nodes
These form a line directly below the inguinal ligament and receive lymph from the penis, scrotum, perineum, buttock and abdominal wall.
- Superficial Sub-Inguinal Nodes
These are located on each side of the proximal section of the great saphenous vein. They receive afferent input primarily from the superficial lymphatic vessels of the lower leg.
- Deep Sub-Inguinal Nodes
These are often found in one to three in number and are most commonly found on the medial aspect of the femoral vein. The afferent supply to these nodes is from the deep lymphatic trunks of the thigh which accompany the femoral vessels.
Outline the investigation of osteoarthritis in terms of bloods, imaging and radiological findings.
- Bloods – FBC, U&Es (urea and electrolytes), LFTs (liver function test), ESR (erythrocyte sedimentation route), CRP
- Imaging – 4 cardinal signs on an X Ray
I. Subchondrial sclerosis
II. Osteophytes
III. Narrowing of joint space
IV. Subchondrial cysts
- Radiological findings of OA
I. Narrowing of joint space
II. Osteophytes
III. Subchondral sclerosis
IV. Bone cysts
Outline the structure of the hip joint
- The two symmetrical hip bones are part of the pelvic girdle
- The pelvic girdle is the bony structure that attaches the axial skeleton to the lower limbs
- The hip bones have three articulations:
I. Sacroiliac joint – articulation with sacrum.
II. Pubic symphysis – articulation with the corresponding hip bone.
III. Hip joint – articulation with the head of femur.
Describe the composition of the hip joint before, during and after puberty
- The hip bone is made up of the three parts – the ilium, pubis and ischium.
- Prior to puberty, the triradiate cartilage separates these constituents.
- At the age of 15-17, the three parts begin to fuse.
- Their fusion forms a cup-shaped socket known as the acetabulum, which becomes complete at 20-25 years of age.
- The head of the femur articulates with the acetabulum to form the hip joint.
Outline the structure of the ilium
- The superior part of the hip bone is formed by the ilium, the widest and largest of the three parts.
- The body of the ilium forms the superior part of the acetabulum.
- Immediately above the acetabulum, the ilium expands to form the wing.
- The wing of the ilium has two surfaces. The inner surface is concave, and known as the iliac fossa, providing origin to the iliacus muscle. The external surface is convex, and provides attachments to the gluteal muscles. Hence it is known as the gluteal surface.
- The superior margin of the wing is thickened, forming the iliac crest. It extends from the anterior superior iliac spine to the posterior superior iliac spine.
Which muscles attach to the ilium?
- Gluteal muscles attach to the external surface of the Ilium at the anterior, posterior and inferior gluteal lines.
- The iliacus muscle attaches medially at the iliac fossa.
Outline the structure of the pubis
- The pubis is the most anterior portion of the hip bone. It consists of a body and superior and inferior rami (branches).
- The body is located medially, articulating with its opposite pubic body, at the pubic symphysis.
- The superior ramus extends laterally from the body, forming part of the acetabulum.
- The inferior ramus projects towards, and joins the ischium.
- Together, the two rami enclose part of the obturator foramen, through which the obturator nerve, artery and vein pass through to reach the lower limb.
Outline the structure of the ischium
- The posterioinferior part of the hip bone is formed by the ischium. Much like the pubis, it is composed of a body, an inferior and a superior ramus.
- The inferior ischial ramus combines with the inferior pubic ramus forming the ischiopubic ramus which encloses part of the obturator foramen.
- The posterorinferior aspect of the ischium forms the ischial tuberosities and when sitting, it is these tuberosities on which our body weight falls.
- On the posterior aspect of the ischium there is an indentation known as the greater sciatic notch, with the ischial spine at its most inferior edge.
Which ligaments attach to the ischium?
Two important ligaments attach to the ischium:
- The sacrospinous ligament runs from the ischial spine to the sacrum, thus creating the greater sciatic foramen through which lower limb neurovasculature (including the sciatic nerve) transcends.
- The sacrotuberous ligament runs from the sacrum to the ischial tuberosity, forming the lesser sciatic foramen
Outline the clinical relevance of fractures to the pelvis bone
- There are two common ways of fracturing the pelvic bones:
I. Direct trauma to the pelvic bones, for example from a vehicular accident.
II. Forces transmitted from the lower limb, for example a heavy fall on the feet.
- Fractures often occur at the weaker points of the bones. These are the pubic rami, the acetabulum or in the region of the sacroiliac joint.
- A common complication of pelvic fractures is soft tissue injury. In particular, the bladder and urethra are at high risk of damage.
