L11.3 Evolution of UL & LL Flashcards
1
Q
Resemblance of UL & LL to ancestry
A
- Retain UL ancestry characteristics
- Derived new LL morphology
2
Q
Intermembral index
A
Intermembral index = (Humerus + Radius)/(Femur + Tibia)
Tells you if animal is UL dominant or LL dominant (>100 = UL dominant)
3
Q
5) UL (10)
A
- Glenoid cavity
- Supraglenoid tubercle
- Greater tubercle
- Deltoid tuberosity
- Scapula
- Supraspinous fossa
- Humero-ulnar joint
- Distal radius
- Phalanges
- Muscles of the hand
4
Q
UL: Glenoid cavity
A
- Humans: Shallow, wide, round & flat; LAT oriented
- Monkeys: Narrow, elongated & Concave; Vertically oriented
- Narrow cavity restricts side movements and elongated cavity allows ANT/POS movements
5
Q
UL: Supraglenoid tubercle
Greater tubercle
Deltoid tuberosity
A
- Supraglenoid tubercle :
- Humans: Projection absent → allows above arm movements
- Monkeys: Projected → limits hyperflexion of arm
- Greater tubercle:
- Humans: Lower than monkeys
- Deltoid tuberosity:
- Humans: lower than monkeys
- Fibres of deltoids are longer → allows greater moment arm of deltoid
- Humans: lower than monkeys
6
Q
UL: Scapula
Spinous Fossa
A
- Scapula:
- Apes: Longer spine scapula (& ↑ size), coronoid process more LAT
- Fibres of trapezius inserts further LAT → ↑cranial rotation (pronation with serratus ANT)
- Also have Dorsoepitrochlearis muscles (deep to LH of triceps) → ↑ extension
- Supraspinous fossa
- Apes: Larger fossa → ↑supraspinatus → allows initiation of abduction
7
Q
UL: Humero-ulnar joint
Distal radius
A
- Humero-ulnar joint:
- Apes:
- Olecranon fossa deeper
- Sharp LAT trochlear ridge
- Olecranon process not projected too far
- All allows hyperextension of joint (support for knuckle walking)
- Apes:
- Distal radius:
- Apes: Bony projection → stabilising & prevents overextension of wrist
8
Q
UL: Phalanges
Muscles of the hand
A
- Phalanges:
- Humans: Broad, flat, long phalanges, opposable & more robust thumb → precision & power grip
- Apes: Long, curved phalanges & short thumb → hook grip
- Muscles of the hand:
- Humans: FPL, FPB more developed
- Apes: FDS, FDP more developed
- Also have contrehentes muscles → allows hook grip
9
Q
Difference b/w human & ape LL
A
- Humans: muscles (plantar flexors & erector spinae) helps with weight transfer
- Apes: LL don’t take much weight, CoG not well balanced walking bipedally
10
Q
Human gait cycle
A
- Heel strike (start): Dorsiflexors in concentric contraction
- Has double support (from both feet)
- Loading response - Foot flat - Dorsiflexors eccentric
- Midstance
- Heel off (terminal): plantarflexors concentric
- Beginning of swing phase - entire weight on 1 leg - point where glut med & min prevents nutation
- Pressing (toes off)
- Has double support
- Initial & midswing
- Heel strike again (cycle begins again)
11
Q
6) LL (6)
A
- Pelvis
- Femur
- Femoral condyles
- Tibia
- Foot
- Muscles of the foot
12
Q
Pelvis
Sciatic Notch
A
- Pelvis:
- Humans: bowl shaped, iliac blades ANT/LAT position → allows glut med/min have LAT position → Ab & InR
- Apes: Longer, POS iliac blades → Gluteals → extension
- Sciatic notch:
- Humans: Deep
- Apes: Shallow
13
Q
LL: Femur
A
- Humans:
- Bicondyle angle of femur - causes valgus knee
- Large femoral head
- Long neck of femur
- Apes:
- Narrow bicondylar angle
- Shorter, slender, curved shafts
- Absolutely smaller femoral head
- Shorter neck → ↓moment arm of gluteals
14
Q
Femoral condyle
A
- Humans: Elliptical outline
- Allows ↑ congruency b/w tibia & distal femur
- Places patellar more fwd → ↑ moment arm of quads
- Apes: Rounded
15
Q
LL: Tibia
A
- Humans:
- Robust & WB
- Shaft oriented perpendicular to proximal articular surfaces
- LAT plateau only 92% of MED → allows locking of knee
- Fibular slender & NWB
- Apes:
- Tibia not as robust
- LAT tibial plateau 84% of MED → able to have greater rotation → joint more mobile
- Fibular more mobile & robust
