The pectoralis major is a muscle that does not attach to the ribs or the iliac crest. Instead, it primarily originates from the clavicle and the sternum and inserts into the humerus. Its primary functions include shoulder flexion, adduction, and internal rotation.
The rectus abdominis muscle originates on the pubic crest and pubic symphysis and inserts on the cartilage of the 6th and 7th ribs and the xiphoid process. It is responsible for flexing the lumbar spine and compressing the abdominal contents.
Ribs 11 and 12 do not attach anteriorly to the sternum.
All attach to a vertebra, The upper 6 also attach to the sternum, the bottom 6 just "float".
The bony landmarks are: iliac crest (a good place to put you hands on), anterior superior iliac spine (that "bump" you can feel on either side of your stomach if it is flat), symphysis pubis (between the legs), sacral promontory which you can not feel but is above the leaf shaped tail bone called the sacrum. Plus the lower ribs and end of the sternum.
There is no "rib muscle." Ribs are bones attached to the vertebral column in the back and the sternum anteriorly. There are muscles attached to the ribs - several, in fact. In between the ribs are the internal and external intercostal muscles, there are the pectoral muscles, the serratus anterior and serratus ventralis, the latissimus dorsi also attaches to the ribs. Internally, the diaphragm attaches to the inferior ribs. Many of the strap muscles of the back attach to the ribs. There are others as well.
The scalenus anterior and the scalenus medius all insert into the first rib (the scalenus posterior inserts into the second rib). They originate from cervical vertebrae two to cervical vertebrae seven (C2 - C7). Each of the scalene muscles has several points of origin, which look like fingers from your spine.
Ribs are classified according to their attachment to the sternum. The first seven pairs of ribs attach directly to the sternum and are called true ribs. Ribs 8-10 have cartilage that attaches to the cartilage of the seventh rib and are called false ribs. The eleventh and twelfth ribs do not attach to the sternum and are called floating ribs.
True Ribs
they are defined as floating ribs
12 vertebrae have ribs attatched
The pectoralis minor originates on the third to the fifth ribs (and elevates ribs). It depresses the scapula (and elevates ribs).
There are twelve pair of ribs. The first seven ribs are true ribs because they have direct attachment to the sternum. An additional three pair of ribs have indirect attachment to the sternum meaning that they attach to other structures that attach to the sternum. The last two ribs are called floating ribs because they do not attach to the sternum at all. Because the floating ribs do not attach to the sternum they are prone to injury.