Spring 1982 - Athletic Training History

• The Schering SymposiumGroinGroin and Hamstring Injuriesand hamstring muscle injuries frequentlyoccur in athletic activity. They are painful, debilitatingand frequently chronic in nature. Understandingthe anatomy and cause of these injuries can be helpful inprevention, treatment, rehabilitation and insuring rapidreturn to normal athletic function.AnatomyThe Hamstring muscles consist of the Semitendinosus,Biceps Femoris, Semimembranosus, and the posteriorportion of the Adductor Magnus. These muscles arisefrom the ischial tuberosity and all, with the exception ofthe Adductor Magnus, are two joint muscles crossing boththe hip joint and the knee (Figure 1).The Semitendinosis produces simultaneous flexion ofthe knee and extension of the thigh, and can produce someadduction and inward rotation at the hip.The Biceps Femoris, as per its name, has two heads: thelong head extending downward and laterally from theischial tuberosity, and the short head arising from thelateral tip of the linea aspera. The short head is the moreDr. Casperson is in the practice of Orthopedic Surgery, 1125 E.17th Street, Suite N 360, Santa Ana, CA 92701.Paul C. Casperson, MDEdited byDon Kaverman, ATCpotent flexor at the knee and the long head is a potentextensor of the hip. The biceps has two motor points: onemotor point is innervated by the tibial nerve and thesecond motor point is innervated by the peroneal nerve.The Biceps Femoris is classified by Grant as a hybridmuscle and it is felt by Burkett that this dual innervationmay be one of the etiologies of hamstring tear. That is,contraction of the quadriceps and the short head of theBiceps Femoris occurs simultaneously and the dualinnervation of the Biceps Femoris could pose a potentialneural mechanism for hamstring strains.The Semimembranosus arises from the ischialtuberosity, extends down the posterior surface of theAdductor Magnus and has multiple insertions about theknee. It also may act independently at the hip and theknee.The Adductor Magnus, posterior portion, arises fromthe ischial tuberosity and inserts above the knee in theadductor tubercle. This is the only one of the hamstringmuscles that does not cross the knee joint. It also acts asan adductor and serves as a rotator of the hip.The groin muscles are divided into anterior and medialgroups. The anterior group is made up of the Sartorius,the Quadriceps, and the Rectus Femoris (Figure 2). TheSartorius is the longest muscle in the body and arises fromFigure 1. HAMSTRING MUSCLES - Semitendinosus,Biceps Femorus, Semimembranosus, Adductor Magnus(posterior portion).Figure 2. GROIN MUSCLES - ANTERIOR GROUP -Sartorius, Quadriceps, Rectus Femoris.Athletic Training • Spring 1982 43