lecture 9, the appendicular skeleton

the appendicular skeleton

• consists of 126 bones

  • the pectoral girdle

  • the pelvic girdle

  • the upper and the lower limbs

the pectoral girdle

• consists of the clavicle and the scapula

  • a. the clavicle

    • this is the collarbone

    • articulates with the manubrium of the sternum and the acromion process of the scapula

    • forms the connection between the axial and the appendicular skeleton

  • b. the scapula (long and thin)

    • acromion process articulates with the clavicle

    • the cavity referred to as the glenoid fossa or the glenoid cavity articulates with the head of the humerus → upper limb bone

    • together the glenoid fossa and the humerus from the shoulder

    • the muscles of the arm and the chest are attached by the coracoid process

the pelvic girdle

• composed of two os coxa

• each os coxa has

  • a. an ilium which articulates with the sacrum at the iliac crest (point of connection of the axial and appendicular)

  • b. an ischium

    • the inferior surface is called the ischial tuberosity

      • the part of the pelvis we sit on

    • bears the weight of the body while sitting

  • c. a pubic bone

    • the two pubic bones are joined by a cartilaginous disk called a public symphysis

    • strip of cartilage

      • helps with childbirth

      • gives flex and protect against erosion

joints in the pelvic girdle

1. the sacroiliac joint

   • a synovial joint

     • have fluid and reinforcement

     • meant for joints with lots movements

2. the public symphysis

   • joins the two pubic bones

     • 2 bones when they mate in the middle

   • formed from cartilage

     • avascular

3. the acetabulum

   • the socket that articulates with the head of the femur (upper leg bone)

     • the hip bone

   • a synovial joint

     • ball and socket

       • free range of motion

       • fluid filled

upper and lower limbs: the arms

(numbers are 1 per arm)

• ALWAYS SHOWN PALM FACING UPP

• humerus

• radius/ulna

• carpals

  • 2 rows of bones per wrist

• 5 metacarpals

  • the palm

• 14 phalanges

the upper and lower limbs: the leg

(numbers are 1 per leg)

• femur

  • harder to break because bigger

• tibia/fibula/patella

• 7 tarsals (ankle)

  • calcaneus is the largest tarsal

  • forms the heel

• 5 metatarsals

  • the sole of the feet

• 14 phalanges

anatomical position of upper and lower limbs

1. medial bones

   • ulna

   • tibia

   • bones of the big toe

   • bones of the little finger → PALMS FACING UP

2. lateral bones

   • radius (in line with the thumb)

   • fibula (in line with the bones of the little toe)