Gluteal Region & Hip Movers - Booty Powerhouse
Key muscles responsible for hip movement and stability.
| Muscle | Action | Nerve Supply |
|---|---|---|
| Gluteus Maximus | Chief extensor; lateral rotation | Inferior gluteal n. |
| Gluteus Medius | Abduction; medial rotation (anterior fibers) | Superior gluteal n. |
| Gluteus Minimus | Abduction; medial rotation (anterior fibers) | Superior gluteal n. |
| Tensor Fasciae Latae (TFL) | Flexion, abduction, medial rotation of hip; stabilizes knee | Superior gluteal n. |
⭐ Trendelenburg Sign: Weakness of Gluteus Medius/Minimus (abductors) leads to pelvic drop on the contralateral (swinging) side during gait. Caused by Superior Gluteal Nerve injury.
📌 Mnemonic for Superior Gluteal Nerve: Gluteus Medius, Gluteus Minimus, TFL (Go Medical To Save Glutes).
Thigh Compartments - Quad Goals & Hammy Time
Thigh: 3 fascial compartments with distinct muscles, actions, innervation.
| Compartment | Key Muscles | Primary Actions | Nerve Supply |
|---|---|---|---|
| Anterior | Quadriceps (Vastus spp., Rectus femoris), Sartorius | Knee extension; Hip flexion | Femoral n. |
| Posterior (Hamstrings) | Biceps femoris, Semitendinosus, Semimembranosus | Knee flexion; Hip extension | Sciatic n. (Tibial div.; Common peroneal for Biceps short head) |
| Medial (Adductors) | Adductor (longus, brevis, magnus), Gracilis | Hip adduction | Obturator n. (Adductor magnus also Sciatic n. - tibial) |
- 📌 Fem-O-Sci Mnemonic: Femoral (Anterior), Obturator (Medial), Sciatic (Posterior).
Leg Compartments - Shin Splints & Calf Kings
Leg Compartments Overview:
| Compartment | Muscles | Actions | Nerve Supply |
|---|---|---|---|
| Anterior | Tibialis Anterior, EHL, EDL, Fibularis Tertius | Dorsiflexion, Inversion, Toe Ext. | Deep Peroneal N. |
| Lateral | Fibularis Longus & Brevis | Eversion, Plantarflexion | Superficial Peroneal N. |
| Posterior (Superf.) | Gastrocnemius, Soleus, Plantaris | Plantarflexion, Knee Flex. (Gastroc) | Tibial N. |
| Posterior (Deep) | Tibialis Posterior, FDL, FHL, Popliteus | Plantarflexion, Inversion, Toe Flex. | Tibial N. |
Clinical Focus:
- Shin Splints (MTSS): Overuse injury; pain along posteromedial tibia.
- Calf Kings: Gastrocnemius & Soleus - powerful plantarflexors (Achilles tendon).
⭐ Foot drop results from damage to the common peroneal nerve or its deep peroneal branch, affecting anterior compartment muscles.
Foot Intrinsic Muscles - Sole Survivors
- Plantar Layers (4): Toe action, arch support.
- L1: Abd Hallucis, Flex Digit Brevis, Abd Digiti Minimi.
- L2: Quad Plantae, Lumbricals.
- L3: Flex Hallucis Brevis, Add Hallucis, Flex Digiti Minimi Brevis.
- L4: Interossei (PAD: Adduct; DAB: Abduct).
- Innervation (Plantar):
- Medial Plantar N.: 1st Lumbrical, Abd Hallucis, Flex Digit Brevis, Flex Hallucis Brevis. (📌 LAFF)
- Lateral Plantar N.: Rest.
- Dorsal: Ext. Digit/Hallucis Brevis (Deep Peroneal N.).
⭐ The Lateral Plantar Nerve innervates most intrinsic foot muscles, analogous to the Ulnar Nerve in the hand for intrinsic hand muscles (except Thenar & lateral 2 Lumbricals).
High‑Yield Points - ⚡ Biggest Takeaways
- Gluteus maximus: chief thigh extensor; supplied by inferior gluteal nerve.
- Trendelenburg sign: indicates gluteus medius/minimus weakness; superior gluteal nerve injury.
- Quadriceps femoris: primary knee extensor group; innervated by femoral nerve.
- Hamstrings: main knee flexors & hip extensors; primarily sciatic nerve (tibial division).
- Foot drop: results from common peroneal nerve injury; paralysis of ankle dorsiflexors.
- Sartorius: "tailor's muscle"; acts on hip & knee; femoral nerve.
- Adductor magnus: unique dual innervation by obturator and sciatic nerves (tibial part).
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