Shoulder and Embryonic Limbs
Intro
Limbs
Limbs grow out of the body wall
Upper limbs: segments C5 to T1
Lower limbs: Segments L2 to S3
Lateral outgrowths
Rotate to gain final position
The foot is not the lower end of the
body
Embryonic position and rotation
The thumb and the big toe point towards the head end
Little finger and little toe point towards the tail end
If we consider the axis (centre line) of the limbs:
Limbs have preaxial (cranial) and postaxial (caudal) borders
Thumb and great toe are preaxial
Little finger and little tow are postaxial
Muscles Groups
Limbs muscles are also organised
Limbs retain embryonic orientation
Shoulder and Embryonic Limbs Intro 1
, Dorsal and ventral surfaces
Musle groups: Dorsal + ventral
Dorsal muslces: extensors and abductors
Ventral: flexsors and adductors
Limb Plan:
Common plan:
Anchoring to the trunk: Girdle
Proximal segment: Arm/thigh: one bone
Distal segment: Forearm/leg: two bones
Wrist/ankle region: small bones
Hand, foot
Upper limb:
Used to reach out, grasp and handle things
High mobility
Lower limbL Support and locomotion:
Less mobile, more stable
Synovial Joint
Two or more bones
Movable surfaces, articular surfaces
Covered by hyaline cartilage
Fibrous capsule: collar of sense fibrous tissue
Lined by synovial membrane
Capsule strengthened further by ligaments where necessary
Bursae: sacs of synovial membrane outside a joint
Reduce friction between joint and nearby structures.
May communicate with joint cavity
Shoulder and Embryonic Limbs Intro 2
Intro
Limbs
Limbs grow out of the body wall
Upper limbs: segments C5 to T1
Lower limbs: Segments L2 to S3
Lateral outgrowths
Rotate to gain final position
The foot is not the lower end of the
body
Embryonic position and rotation
The thumb and the big toe point towards the head end
Little finger and little toe point towards the tail end
If we consider the axis (centre line) of the limbs:
Limbs have preaxial (cranial) and postaxial (caudal) borders
Thumb and great toe are preaxial
Little finger and little tow are postaxial
Muscles Groups
Limbs muscles are also organised
Limbs retain embryonic orientation
Shoulder and Embryonic Limbs Intro 1
, Dorsal and ventral surfaces
Musle groups: Dorsal + ventral
Dorsal muslces: extensors and abductors
Ventral: flexsors and adductors
Limb Plan:
Common plan:
Anchoring to the trunk: Girdle
Proximal segment: Arm/thigh: one bone
Distal segment: Forearm/leg: two bones
Wrist/ankle region: small bones
Hand, foot
Upper limb:
Used to reach out, grasp and handle things
High mobility
Lower limbL Support and locomotion:
Less mobile, more stable
Synovial Joint
Two or more bones
Movable surfaces, articular surfaces
Covered by hyaline cartilage
Fibrous capsule: collar of sense fibrous tissue
Lined by synovial membrane
Capsule strengthened further by ligaments where necessary
Bursae: sacs of synovial membrane outside a joint
Reduce friction between joint and nearby structures.
May communicate with joint cavity
Shoulder and Embryonic Limbs Intro 2
