Test: Skeletal System & Joints - JAMB MCQ

Pectoral girdle is the bony or cartilaginous structure in vertebrates to which the anterior limbs (pectoral fins, forelegs or arms) are attached. In mammals, it consists of two dorsal scapula (shoulder blades) attached to the backbone and two ventral clavicles (collar bones) attached to the sternum (breast bone).

There are 12 pairs of ribs. First seven pairs of ribs are called true ribs. Dorsally, they are attached to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage. The 8th, 9th and 10th pairs of ribs do not articulate directly with the sternum but join the seventh rib with the help of hyaline cartilage. These are called vertebrochondral (false) ribs. Last 2 pairs (11th and 12th) of ribs are not connected ventrally and are therefore, called floating ribs.

Humans have twelve pairs of cranial nerves, three pairs of salivary glands and one pair of collar bones.

In humans, the vertebral column is formed by 26 serially arranged units called vertebrae and is dorsally placed.
Each vertebra has a central hollow portion (neural canal) through which the spinal cord passes.
The vertebral column is differentiated into cervical (7), thoracic (12), lumbar (5), sacral (1-fused) and coccygeal (1-fused) regions starting from the skull
Hence Number of vertebrae present on cervical, thoracic, lumbar, sacral and coccyx regions are respectively 7,12,5,1,1.
So,the correct answer is '7, 12, 5, 1, 1'.

The pelvic girdle, as above, is made up of three fused bones: the ischium, the ilium, and the pubis. The pubis forms the anterior part of the pelvic girdle. It is a flattened, irregular-shaped bone that articulates with the pubic symphysis, a cartilaginous joint.

The hyoid bone is a U – shaped bone which is located at the base of the buccal cavity. It is a single bone and is included along with the bones of the skull. The skull possesses a total of 22 bones.

10. The inner ear cont

The synovial membrane secretes a watery fluid that lubricates and cushions the joint.
The synovial membrane is a specialized connective tissue membrane that lines the inner surface of the joint capsule. It is responsible for secreting synovial fluid, which is a clear, viscous fluid that lubricates the joint and reduces friction between the bones. Here is a detailed explanation of why the synovial membrane is the correct answer:
1. Structure of the synovial membrane:
- The synovial membrane is a thin layer of tissue that lines the joint cavity.
- It consists of two layers: an outer fibrous layer and an inner synovial layer.
- The synovial layer contains specialized cells called synoviocytes, which are responsible for producing synovial fluid.
2. Function of synovial fluid:
- Synovial fluid acts as a lubricant, reducing friction between the moving surfaces of the joint.
- It provides nourishment to the articular cartilage, which does not have a direct blood supply.
- It helps in shock absorption, cushioning the joint and protecting it from impact.
3. Composition of synovial fluid:
- Synovial fluid is a clear, viscous fluid that resembles egg whites.
- It is primarily composed of water, which gives it its watery consistency.
- It also contains hyaluronic acid and lubricin, which further contribute to its lubricating properties.
4. Role of the synovial membrane:
- The synovial membrane is responsible for the production and secretion of synovial fluid.
- It constantly produces and reabsorbs synovial fluid to maintain the proper amount within the joint cavity.
- The synovial membrane also helps in removing waste products and inflammatory mediators from the joint.
In conclusion, the synovial membrane is the correct answer as it secretes a watery fluid called synovial fluid, which lubricates and cushions the joint, reducing friction and providing nourishment and shock absorption to the joint structures.

The first seven pairs of ribs are called true ribs because they are directly attached to the sternum via hyaline cartilage.

The femur is a bone of the lower limb and part of the appendicular skeleton. The skull, vertebral column, and sternum are part of the axial skeleton.

The scapula has a depression called the glenoid cavity, which articulates with the head of the humerus to form the shoulder joint.

Humans possess two occipital condyles. Hence, humans have a dicondylic skull. The function of the occipital condyles is to articulate the skull region with the superior region of the vertebral column.