VIVA: Anatomy - Lower limb Flashcards
What are the myotomes of the lower limb?
6/10 to pass:
- Hip flexion L2/3
- Hip extension L4/5
- Knee extension L3/4
- Knee flexion L5/S1
- Ankle flexion L4/5
- Ankle extension S1/2
- Inversion L4
- Eversion L5/S1
- Big toe flexion L5/S1
- Big toe extension S1/2
Using this diagram, demonstrate the cutaneous nerve supply of the leg
5 to pass:
- Lateral thigh: lateral cutaneous nerve of thigh
- Anterior and medial thigh: anterior cutaneous branch of femoral nerve, intermediate and medial femoral cutaneous nerves, obturator nerve
- Posterior thigh: posterior cutaneous nerve of thigh
- Lateral leg from knee to mid-calf: lateral cutaneous nerve of calf and leg
- Anterolateral leg from mid-calf: superficial peroneal (fibular) nerve
- Posterolateral leg from mid-calf: sural nerve
- Medial leg: saphenous nerve
- Dorsum of foot, except 1st web space: superficial peroneal (fibular) nerve
- Heel: medial calcaneal branch of tibial nerve
- Sole of foot except heel: medial and lateral plantar branches of tibial nerve
Describe the anatomy of the inguinal canal
- Oblique, inferomedial passage, 4cm long, superior to the medial 1/2 of the inguinal ligament
- Deep (internal) ring superior to middle of inguinal ligament* and lateral to inferior epigastric artery
- Superficial (external) ring superolateral to pubic tubercle*, formed by split in external oblique aponeurosis
- Anterior wall: external oblique aponeurosis
- Posterior wall: transversalis fascia (+ conjoint tendon)
- Roof: transversalis fascia, internal oblique and transversus abdominis
- Floor: inguinal ligament
*needed to pass + basic concepts of walls, roof and floor
What is the difference between a direct and indirect inguinal hernia?
Direct (acquired):
- Weakness of anterior abdominal wall
- Traverses medial 1/3 of canal and exits at superficial ring lateral to cord
- Rarely enters scrotum
Indirect (congenital):
- Traverses entire canal within patent processus vaginalis
- Goes from deep to superficial ring
- Inside cord, so commonly enters scrotum or labia majora
A patient with a known inguinal hernia presents with a tender lump in the groin. What underlying structures may be involved in this lump?
- Small bowel*
- Large bowel
- Mesentery/omentum
- Other abdominal or pelvic viscera (e.g. bladder, ovaries, appendix)
*needed to pass + 1 other
Identify the bony landmarks of the pelvis
Bones:
- Ilium*
- Ischium*
- Pubis*
Surface:
- Iliac crest*
- ASIS*
- AIIS*
- Ischial tuberosity*
- Ischial spine
- PSIS
- PIIS
- Symphysis pubis*
Joints:
- SIJ*
- Acetabulum/femur*
- Symphysis pubis*
Other:
- Pubic rami* (4)
- Ala of ilium
- Greater and lesser sciatic notches
- Obturator foramen
*needed to pass
Identify on the model the ligaments of the hip joint and their attachments
- Iliofemoral *:
- AIIS/acetabular rim to intertrochanteric line * - Pubofemoral *:
- Obturator crest to capsule and iliofemoral ligament * - Ischiofemoral:
- Acetabular rim to base of greater trochanter
*needed to pass
Where on this model might you find a pathological fracture?
1 to pass:
- Pubic rami
- Neck of femur
- Proximal shaft
Identify the boundaries of the femoral triangle on this photo
3 to pass:
- Superior: inguinal ligament (13)
- Medial: lateral border of adductor longus (1)
- Lateral: medial border of sartorius (19)
- Floor: iliopsoas (11) and pectineus (15)
Identify the contents of the femoral triangle on this photo
- Femoral nerve* (7)
- Femoral artery* (6)
- Femoral vein* (8)
- Deep inguinal lymph nodes
- Lymphatics
*2/3 to pass
What are the origin and terminal branches of the femoral artery?
Origin of femoral artery = external iliac artery*
Terminal branches of femoral = profunda femoris* (deep to adductor longus) and superficial femoral artery*
*need origin + one terminal branch to pass
Which spinal roots is the femoral nerve derived from?
L2, L3, L4
What anterior thigh muscles does the femoral nerve innervate?
4/6 to pass:
- Sartorius
- Articularis genu
- Quadriceps including rectus femoris, vastus medialis, vastus lateralis and vastus intermedius
What does the femoral nerve supply?
Motor (L2, L3, L4):
- Iliopsoas (hip flexion)
- Quadriceps* (knee extension; deep division): rectus femoris, vastus medialis, vastus lateralis, vastus intermedius
- Sartorius (hip flexion and lateral rotation, hip abduction, knee flexion; superficial division)
- Pectineus (hip flexion and adduction; superficial division)
Sensory:
- Intermediate and medial cutaneous nerve of thigh* (superficial division)
- Cutaneous saphenous (skin of medial leg and foot; deep division)
- Proprioception of hip joint from nerve to rectus femoris
- Proprioception to knee from nerve to vastus medialis
*needed to pass
What surface markings would you look for when trying to locate the femoral vein?
- Artery is located inferior to the inguinal ligament at the mid-inguinal point (midway between ASIS and pubic symphysis)*
- Vein is just medial to artery*
*needed to pass
Which veins drain into the common femoral vein?
- Continuation of the popliteal vein
- Receives the profunda femoris* and great saphenous vein* (7)
- Ends posterior to the inguinal ligament where it becomes the external iliac vein
- Also receives superficial epigastric vein (27), superficial circumflex iliac vein (25), and superficial external pudendal vein (28)
*needed to pass
Identify the proximal landmarks of the femur on this XR
- Head* with fovea for ligament of head
- Neck*
- Greater and lesser trochanters*
- Shaft*
- Intertrochanteric line (anterior) and crest (posterior)
- Quadrate tubercle
- Pectineal line
- Gluteal tuberosity
- Linea aspera with medial and lateral lips
Describe the blood supply to the head of the femur
- Medial and lateral circumflex femoral arteries *:
- Usually branches of the deep artery of thigh (profunda femoris)
- Branch to form retinacular arteries (medial > lateral)
- Medial feeds under posterior unattached capsule, lateral through iliofemoral ligament
- Posterior retinacular arteries from medial circumflex are most important, lateral circumflex contributes a little via cruciate anastomosis
- Distal to proximal * - Artery to head of femur (foveal artery; less important):
- Branch of obturator artery
*needed to pass
Describe the bony features of the middle and lower end of the femur
5/8 to pass:
1. Linea aspera
2. Medial supracondylar ridge:
- Inferior continuation of the medial lip of the linea aspera
- Interrupted to allow passage of the femoral artery
- Ends in adductor tubercle
3. Lateral supracondylar ridge:
- Descends to lateral epicondyle
4. Medial condyle
5. Lateral condyle
6. Intercondylar fossa
7. Adductor tubercle
8. Attachment of the medial ligament (medial epicondyle)
Which muscles attach to the linea aspera?
3/6 to pass:
- Vastus medialis
- Vastus lateralis
- Adductor brevis
- Adductor longus
- Adductor magnus
- Short head of biceps femoris
Which artery is most likely to be damaged by a fracture of the midshaft of the femur?
Profunda femoris
What is the course of the femoral artery through the thigh?
- Continuation of external iliac artery as it crosses under the inguinal ligament at the mid-inguinal point and enters the femoral triangle
- Gives off profunda femoris and continues as superficial femoral artery
- After exiting the femoral triangle, it enters the adductor canal and continues down the anterior thigh
- Exits the adductor canal at the adductor hiatus (opening in the adductor magnus) and enters posterior compartment of the thigh just proximal to the knee, where it becomes the popliteal artery
Demonstrate on the model the muscular attachments to the greater trochanter
4/7 to pass:
- Vastus lateralis (originates; all others muscles insert)
- Gluteus maximus (some fibres only, most to iliotibial tract)
- Gluteus medius (lateral surface)
- Gluteus minimus (anterior surface)
- Piriformis (superior border)
- Obturator internus (medial surface at trochanteric fossa)
- Superior and inferior gemelli (medial surface)
The patient has a subcapital (intracapsular) fractured neck of femur. What is the most concerning complication of this type of fracture and why does this occur?
Avascular necrosis of femoral head *:
- Hip joint has dual supply * from medial and lateral circumflex arteries * (usually branches of profunda femoris, can arise directly from femoral artery), and artery to head of femur (branch of obturator artery, traverses ligament of head and is often small/inadequate)
- Main supply of femoral head is via retinacular artery from branches of the circumflex femoral * (particularly medial, because these pass freely under unattached posterior border of joint capsule while branches from lateral must penetrate thick iliofemoral ligament and are smaller and fewer)
- Retinacular arteries are torn or disrupted in intracapsular fracture *
*needed to pass