Structure
The proximal femur has four parts: head, neck, greater trochanter and lesser trochanter, joined at the front by the intertrochanteric line and at the back by the intertrochanteric crest.
- Head: about two-thirds of a sphere, facing up, medially and slightly forwards. The fovea, a small pit just below and behind its centre, takes the ligament of the head.
- Neck: joins the head to the shaft at the neck-shaft angle, about 125 degrees in adults and wider in children. It is also angled forwards relative to the knee (anteversion). Many vascular foramina on its upper and back surfaces carry the retinacular arteries.
- Greater trochanter: the large lateral projection at the junction of neck and shaft, palpable on the side of the hip. The trochanteric fossa is a deep pit on its medial surface.
- Lesser trochanter: a conical projection on the posteromedial side below the neck.
- Intertrochanteric line: a rough ridge on the front, for the capsule and the iliofemoral ligament. It continues below as the spiral line.
- Intertrochanteric crest: a smooth, prominent ridge on the back, with the quadrate tubercle near its middle.
Below the trochanters, the gluteal tuberosity runs down the back of the shaft laterally, and the pectineal line runs down medially, both converging on the linea aspera.
Attachments
Nearly every muscle of the gluteal region inserts on the proximal femur, and each has a precise footprint.
| Site | Muscle | Nerve | Action |
|---|---|---|---|
| Lateral surface of greater trochanter | Gluteus medius | Superior gluteal (L4–S1) | Abduction |
| Anterior surface of greater trochanter | Gluteus minimus | Superior gluteal (L4–S1) | Abduction, medial rotation |
| Upper border of greater trochanter | Piriformis | Nerve to piriformis (S1, S2) | Lateral rotation |
| Medial surface of greater trochanter, above the fossa | Obturator internus and gemelli | Nerves to obturator internus and quadratus femoris | Lateral rotation |
| Trochanteric fossa | Obturator externus | Obturator (L3, L4) | Lateral rotation |
| Quadrate tubercle | Quadratus femoris | Nerve to quadratus femoris (L4–S1) | Lateral rotation |
| Lesser trochanter | Iliopsoas | Femoral (iliacus); L1–L3 directly (psoas) | Flexion |
| Gluteal tuberosity | Gluteus maximus (deep lower fibres) | Inferior gluteal (L5–S2) | Extension, lateral rotation |
Vastus lateralis arises from the upper intertrochanteric line and the base of the greater trochanter, and vastus medialis from the lower intertrochanteric line and spiral line. Pectineus inserts along the pectineal line.
Relations and blood supply
The proximal femur is wrapped in muscle, with two neurovascular structures closely applied to it. Behind, the sciatic nerve runs down on the short rotators and quadratus femoris, roughly midway between the greater trochanter and the ischial tuberosity. The deep branch of the medial circumflex femoral artery passes along the upper border of quadratus femoris and up the back of the neck to supply most of the head. In front, the femoral artery lies over the head, separated from it by the psoas tendon and the capsule.
The head receives blood mainly through retinacular vessels on the neck, and only a little through the ligament of the head. The trochanters and shaft have a rich supply from the circumflex and perforating arteries, so fractures there usually heal well.
Clinical relevance
Hip fractures are classified by their relation to the capsule, because that decides both blood supply and treatment.
| Type | Site | Usual treatment |
|---|---|---|
| Intracapsular, undisplaced | Femoral neck | Internal fixation with screws |
| Intracapsular, displaced | Femoral neck | Hemiarthroplasty or total hip replacement |
| Intertrochanteric (extracapsular) | Between the trochanters | Sliding hip screw |
| Subtrochanteric | Just below the lesser trochanter | Intramedullary nail |
The Garden classification grades intracapsular fractures: I incomplete or impacted in valgus, II complete but undisplaced, III complete and partly displaced, IV completely displaced. Grades III and IV disrupt the retinacular vessels. A displaced hip fracture leaves the leg shortened and externally rotated.
- Slipped upper femoral epiphysis: the head slips backwards on the neck through the growth plate in adolescents, often presenting with knee pain.
- Isolated avulsion of the lesser trochanter in an adult suggests a pathological fracture through a metastasis.
- Coxa vara and coxa valga: a neck-shaft angle narrower or wider than normal, altering the abductor lever arm.
On the specimen
The station shows the upper femur with the stumps of its muscles attached, so each marker is identified by footprint. Side the bone first: the head points medially, the greater trochanter is lateral, and the lesser trochanter projects backwards and medially.
On the greater trochanter, the muscle on its front is gluteus minimus and the broad insertion on its lateral surface is gluteus medius; the round tendon reaching its upper border is piriformis. The flat, square muscle attached to the back of the bone at the intertrochanteric crest is quadratus femoris. The thick tendon on the lesser trochanter is iliopsoas. The muscle reaching the gluteal tuberosity and fanning into the iliotibial tract is gluteus maximus.